diff --git a/bin/hardening.sh b/bin/hardening.sh
index bd85e45..e45dca1 100755
--- a/bin/hardening.sh
+++ b/bin/hardening.sh
@@ -180,15 +180,15 @@ if [ -z "$CIS_ROOT_DIR" ]; then
     exit 128
 fi
 # shellcheck source=../lib/constants.sh
-[ -r $CIS_ROOT_DIR/lib/constants.sh ] && . $CIS_ROOT_DIR/lib/constants.sh
+[ -r "$CIS_ROOT_DIR"/lib/constants.sh ] && . "$CIS_ROOT_DIR"/lib/constants.sh
 # shellcheck source=../etc/hardening.cfg
-[ -r $CIS_ROOT_DIR/etc/hardening.cfg ] && . $CIS_ROOT_DIR/etc/hardening.cfg
+[ -r "$CIS_ROOT_DIR"/etc/hardening.cfg ] && . "$CIS_ROOT_DIR"/etc/hardening.cfg
 # shellcheck source=../lib/common.sh
-[ -r $CIS_ROOT_DIR/lib/common.sh ] && . $CIS_ROOT_DIR/lib/common.sh
+[ -r "$CIS_ROOT_DIR"/lib/common.sh ] && . "$CIS_ROOT_DIR"/lib/common.sh
 # shellcheck source=../lib/utils.sh
-[ -r $CIS_ROOT_DIR/lib/utils.sh ] && . $CIS_ROOT_DIR/lib/utils.sh
+[ -r "$CIS_ROOT_DIR"/lib/utils.sh ] && . "$CIS_ROOT_DIR"/lib/utils.sh
 
-if [ $BATCH_MODE ]; then MACHINE_LOG_LEVEL=3; fi
+if [ "$BATCH_MODE" ]; then MACHINE_LOG_LEVEL=3; fi
 
 # If --allow-service-list is specified, don't run anything, just list the supported services
 if [ "$ALLOW_SERVICE_LIST" = 1 ]; then
@@ -223,7 +223,7 @@ if [ -n "$SET_HARDENING_LEVEL" ] && [ "$SET_HARDENING_LEVEL" != 0 ]; then
     exit 0
 fi
 
-if [ $CREATE_CONFIG = 1 ] && [ "$EUID" -ne 0 ]; then
+if [ "$CREATE_CONFIG" = 1 ] && [ "$EUID" -ne 0 ]; then
     echo "For --create-config-files-only, please run as root"
     exit 1
 fi
diff --git a/bin/hardening/1.1.1.3_disable_hfs.sh b/bin/hardening/1.1.1.3_disable_hfs.sh
index bdfd696..dbb4bb2 100755
--- a/bin/hardening/1.1.1.3_disable_hfs.sh
+++ b/bin/hardening/1.1.1.3_disable_hfs.sh
@@ -22,7 +22,7 @@ MODULE_FILE="hfs"
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    is_kernel_option_enabled "$KERNEL_OPTION" $MODULE_FILE
+    is_kernel_option_enabled "$KERNEL_OPTION" "$MODULE_FILE"
     if [ "$FNRET" = 0 ]; then # 0 means true in bash, so it IS activated
         crit "$KERNEL_OPTION is enabled!"
     else
diff --git a/bin/hardening/1.1.1.4_disable_hfsplus.sh b/bin/hardening/1.1.1.4_disable_hfsplus.sh
index 615c14a..7527ca0 100755
--- a/bin/hardening/1.1.1.4_disable_hfsplus.sh
+++ b/bin/hardening/1.1.1.4_disable_hfsplus.sh
@@ -22,7 +22,7 @@ MODULE_FILE="hfsplus"
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    is_kernel_option_enabled "$KERNEL_OPTION" $MODULE_FILE
+    is_kernel_option_enabled "$KERNEL_OPTION" "$MODULE_FILE"
     if [ "$FNRET" = 0 ]; then # 0 means true in bash, so it IS activated
         crit "$KERNEL_OPTION is enabled!"
     else
diff --git a/bin/hardening/1.1.1.5_disable_udf.sh b/bin/hardening/1.1.1.5_disable_udf.sh
index 8273c6a..6516097 100755
--- a/bin/hardening/1.1.1.5_disable_udf.sh
+++ b/bin/hardening/1.1.1.5_disable_udf.sh
@@ -22,7 +22,7 @@ MODULE_FILE="udf"
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    is_kernel_option_enabled "$KERNEL_OPTION" $MODULE_FILE
+    is_kernel_option_enabled "$KERNEL_OPTION" "$MODULE_FILE"
     if [ "$FNRET" = 0 ]; then # 0 means true in bash, so it IS activated
         crit "$KERNEL_OPTION is enabled!"
     else
diff --git a/bin/hardening/1.1.1.7_disable_squashfs.sh b/bin/hardening/1.1.1.7_disable_squashfs.sh
index d9b8212..feaa3dc 100755
--- a/bin/hardening/1.1.1.7_disable_squashfs.sh
+++ b/bin/hardening/1.1.1.7_disable_squashfs.sh
@@ -22,7 +22,7 @@ MODULE_FILE="squashfs"
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    is_kernel_option_enabled "$KERNEL_OPTION" $MODULE_FILE
+    is_kernel_option_enabled "$KERNEL_OPTION" "$MODULE_FILE"
     if [ "$FNRET" = 0 ]; then # 0 means true in bash, so it IS activated
         crit "$KERNEL_OPTION is enabled!"
     else
diff --git a/bin/hardening/1.1.10_var_tmp_noexec.sh b/bin/hardening/1.1.10_var_tmp_noexec.sh
index de5a24d..d1265de 100755
--- a/bin/hardening/1.1.10_var_tmp_noexec.sh
+++ b/bin/hardening/1.1.10_var_tmp_noexec.sh
@@ -56,7 +56,7 @@ apply() {
         crit "$PARTITION is not a partition, correct this by yourself, I cannot help you here"
     elif [ "$FNRET" = 1 ]; then
         info "Adding $OPTION to fstab"
-        add_option_to_fstab $PARTITION $OPTION
+        add_option_to_fstab "$PARTITION" "$OPTION"
         info "Remounting $PARTITION from fstab"
         remount_partition "$PARTITION"
     elif [ "$FNRET" = 3 ]; then
diff --git a/bin/hardening/1.1.14_home_nodev.sh b/bin/hardening/1.1.14_home_nodev.sh
index 5da7307..e3221fb 100755
--- a/bin/hardening/1.1.14_home_nodev.sh
+++ b/bin/hardening/1.1.14_home_nodev.sh
@@ -56,7 +56,7 @@ apply() {
         crit "$PARTITION is not a partition, correct this by yourself, I cannot help you here"
     elif [ "$FNRET" = 1 ]; then
         info "Adding $OPTION to fstab"
-        add_option_to_fstab $PARTITION $OPTION
+        add_option_to_fstab "$PARTITION" "$OPTION"
         info "Remounting $PARTITION from fstab"
         remount_partition "$PARTITION"
     elif [ "$FNRET" = 3 ]; then
diff --git a/bin/hardening/1.1.22_disable_automounting.sh b/bin/hardening/1.1.22_disable_automounting.sh
index fff3322..62eb6e0 100755
--- a/bin/hardening/1.1.22_disable_automounting.sh
+++ b/bin/hardening/1.1.22_disable_automounting.sh
@@ -36,7 +36,7 @@ apply() {
     is_service_enabled "$SERVICE_NAME"
     if [ "$FNRET" = 0 ]; then
         info "Disabling $SERVICE_NAME"
-        update-rc.d $SERVICE_NAME remove >/dev/null 2>&1
+        update-rc.d "$SERVICE_NAME" remove >/dev/null 2>&1
     else
         ok "$SERVICE_NAME is disabled"
     fi
diff --git a/bin/hardening/1.1.3_tmp_nodev.sh b/bin/hardening/1.1.3_tmp_nodev.sh
index 9996b80..95f65e7 100755
--- a/bin/hardening/1.1.3_tmp_nodev.sh
+++ b/bin/hardening/1.1.3_tmp_nodev.sh
@@ -56,7 +56,7 @@ apply() {
         crit "$PARTITION is not a partition, correct this by yourself, I cannot help you here"
     elif [ "$FNRET" = 1 ]; then
         info "Adding $OPTION to fstab"
-        add_option_to_fstab $PARTITION $OPTION
+        add_option_to_fstab "$PARTITION" "$OPTION"
         info "Remounting $PARTITION from fstab"
         remount_partition "$PARTITION"
     elif [ "$FNRET" = 3 ]; then
diff --git a/bin/hardening/1.1.4_tmp_nosuid.sh b/bin/hardening/1.1.4_tmp_nosuid.sh
index d6e3c47..4225bf6 100755
--- a/bin/hardening/1.1.4_tmp_nosuid.sh
+++ b/bin/hardening/1.1.4_tmp_nosuid.sh
@@ -56,7 +56,7 @@ apply() {
         crit "$PARTITION is not a partition, correct this by yourself, I cannot help you here"
     elif [ "$FNRET" = 1 ]; then
         info "Adding $OPTION to fstab"
-        add_option_to_fstab $PARTITION $OPTION
+        add_option_to_fstab "$PARTITION" "$OPTION"
         info "Remounting $PARTITION from fstab"
         remount_partition "$PARTITION"
     elif [ "$FNRET" = 3 ]; then
diff --git a/bin/hardening/1.1.5_tmp_noexec.sh b/bin/hardening/1.1.5_tmp_noexec.sh
index 7d673cd..54fe441 100755
--- a/bin/hardening/1.1.5_tmp_noexec.sh
+++ b/bin/hardening/1.1.5_tmp_noexec.sh
@@ -56,7 +56,7 @@ apply() {
         crit "$PARTITION is not a partition, correct this by yourself, I cannot help you here"
     elif [ "$FNRET" = 1 ]; then
         info "Adding $OPTION to fstab"
-        add_option_to_fstab $PARTITION $OPTION
+        add_option_to_fstab "$PARTITION" "$OPTION"
         info "Remounting $PARTITION from fstab"
         remount_partition "$PARTITION"
     elif [ "$FNRET" = 3 ]; then
diff --git a/bin/hardening/1.1.8_var_tmp_nodev.sh b/bin/hardening/1.1.8_var_tmp_nodev.sh
index f7fbd9e..ea6dd63 100755
--- a/bin/hardening/1.1.8_var_tmp_nodev.sh
+++ b/bin/hardening/1.1.8_var_tmp_nodev.sh
@@ -56,7 +56,7 @@ apply() {
         crit "$PARTITION is not a partition, correct this by yourself, I cannot help you here"
     elif [ "$FNRET" = 1 ]; then
         info "Adding $OPTION to fstab"
-        add_option_to_fstab $PARTITION $OPTION
+        add_option_to_fstab "$PARTITION" "$OPTION"
         info "Remounting $PARTITION from fstab"
         remount_partition "$PARTITION"
     elif [ "$FNRET" = 3 ]; then
diff --git a/bin/hardening/1.1.9_var_tmp_nosuid.sh b/bin/hardening/1.1.9_var_tmp_nosuid.sh
index 1125594..ac9a772 100755
--- a/bin/hardening/1.1.9_var_tmp_nosuid.sh
+++ b/bin/hardening/1.1.9_var_tmp_nosuid.sh
@@ -56,7 +56,7 @@ apply() {
         crit "$PARTITION is not a partition, correct this by yourself, I cannot help you here"
     elif [ "$FNRET" = 1 ]; then
         info "Adding $OPTION to fstab"
-        add_option_to_fstab $PARTITION $OPTION
+        add_option_to_fstab "$PARTITION" "$OPTION"
         info "Remounting $PARTITION from fstab"
         remount_partition "$PARTITION"
     elif [ "$FNRET" = 3 ]; then
diff --git a/bin/hardening/1.4.1_bootloader_ownership.sh b/bin/hardening/1.4.1_bootloader_ownership.sh
index 2309d63..803a374 100755
--- a/bin/hardening/1.4.1_bootloader_ownership.sh
+++ b/bin/hardening/1.4.1_bootloader_ownership.sh
@@ -68,17 +68,17 @@ check_config() {
         warn "Grub is not installed, not handling configuration"
         exit 128
     fi
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
     fi
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         crit "$FILE does not exist"
         exit 128
diff --git a/bin/hardening/1.4.2_bootloader_password.sh b/bin/hardening/1.4.2_bootloader_password.sh
index aad38dd..0585c1b 100755
--- a/bin/hardening/1.4.2_bootloader_password.sh
+++ b/bin/hardening/1.4.2_bootloader_password.sh
@@ -23,13 +23,13 @@ PWD_PATTERN="^password_pbkdf2"
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_pattern_exist_in_file $FILE "$USER_PATTERN"
+    does_pattern_exist_in_file "$FILE" "$USER_PATTERN"
     if [ "$FNRET" != 0 ]; then
         crit "$USER_PATTERN not present in $FILE"
     else
         ok "$USER_PATTERN is present in $FILE"
     fi
-    does_pattern_exist_in_file $FILE "$PWD_PATTERN"
+    does_pattern_exist_in_file "$FILE" "$PWD_PATTERN"
     if [ "$FNRET" != 0 ]; then
         crit "$PWD_PATTERN not present in $FILE"
     else
@@ -39,13 +39,13 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_pattern_exist_in_file $FILE "$USER_PATTERN"
+    does_pattern_exist_in_file "$FILE" "$USER_PATTERN"
     if [ "$FNRET" != 0 ]; then
         warn "$USER_PATTERN not present in $FILE, please configure password for grub"
     else
         ok "$USER_PATTERN is present in $FILE"
     fi
-    does_pattern_exist_in_file $FILE "$PWD_PATTERN"
+    does_pattern_exist_in_file "$FILE" "$PWD_PATTERN"
     if [ "$FNRET" != 0 ]; then
         warn "$PWD_PATTERN not present in $FILE, please configure password for grub"
     else
diff --git a/bin/hardening/1.5.1_restrict_core_dumps.sh b/bin/hardening/1.5.1_restrict_core_dumps.sh
index 0e59d39..f4d6ab9 100755
--- a/bin/hardening/1.5.1_restrict_core_dumps.sh
+++ b/bin/hardening/1.5.1_restrict_core_dumps.sh
@@ -28,7 +28,7 @@ audit() {
     SEARCH_RES=0
     LIMIT_FILES=""
     if $SUDO_CMD [ -d "$LIMIT_DIR" ]; then
-        for file in $($SUDO_CMD ls $LIMIT_DIR/*.conf 2>/dev/null); do
+        for file in $($SUDO_CMD ls "$LIMIT_DIR"/*.conf 2>/dev/null); do
             LIMIT_FILES="$LIMIT_FILES $LIMIT_DIR/$file"
         done
     fi
@@ -43,7 +43,7 @@ audit() {
             break
         fi
     done
-    if [ $SEARCH_RES = 0 ]; then
+    if [ "$SEARCH_RES" = 0 ]; then
         crit "$LIMIT_PATTERN is not present in $LIMIT_FILE $LIMIT_FILES"
     fi
     has_sysctl_param_expected_result "$SYSCTL_PARAM" "$SYSCTL_EXP_RESULT"
@@ -68,7 +68,7 @@ apply() {
     has_sysctl_param_expected_result "$SYSCTL_PARAM" "$SYSCTL_EXP_RESULT"
     if [ "$FNRET" != 0 ]; then
         warn "$SYSCTL_PARAM was not set to $SYSCTL_EXP_RESULT -- Fixing"
-        set_sysctl_param $SYSCTL_PARAM $SYSCTL_EXP_RESULT
+        set_sysctl_param "$SYSCTL_PARAM" "$SYSCTL_EXP_RESULT"
     elif [ "$FNRET" = 255 ]; then
         warn "$SYSCTL_PARAM does not exist -- Typo?"
     else
diff --git a/bin/hardening/1.5.3_enable_randomized_vm_placement.sh b/bin/hardening/1.5.3_enable_randomized_vm_placement.sh
index 92c5eff..c4c6ee7 100755
--- a/bin/hardening/1.5.3_enable_randomized_vm_placement.sh
+++ b/bin/hardening/1.5.3_enable_randomized_vm_placement.sh
@@ -37,7 +37,7 @@ apply() {
     has_sysctl_param_expected_result "$SYSCTL_PARAM" "$SYSCTL_EXP_RESULT"
     if [ "$FNRET" != 0 ]; then
         warn "$SYSCTL_PARAM was not set to $SYSCTL_EXP_RESULT -- Fixing"
-        set_sysctl_param $SYSCTL_PARAM $SYSCTL_EXP_RESULT
+        set_sysctl_param "$SYSCTL_PARAM" "$SYSCTL_EXP_RESULT"
     elif [ "$FNRET" = 255 ]; then
         warn "$SYSCTL_PARAM does not exist -- Typo?"
     else
diff --git a/bin/hardening/1.6.2.1_enable_apparmor.sh b/bin/hardening/1.6.2.1_enable_apparmor.sh
index 023800d..1102ea3 100755
--- a/bin/hardening/1.6.2.1_enable_apparmor.sh
+++ b/bin/hardening/1.6.2.1_enable_apparmor.sh
@@ -36,13 +36,13 @@ audit() {
     c_IFS=$'\n'
     IFS=$c_IFS
     for line in $RESULT; do
-        if [[ ! $line =~ "apparmor=1" ]] || [[ ! $line =~ "security=apparmor" ]]; then
+        if [[ ! "$line" =~ "apparmor=1" ]] || [[ ! "$line" =~ "security=apparmor" ]]; then
             crit "$line is not configured"
             ERROR=1
         fi
     done
     IFS=$d_IFS
-    if [ $ERROR = 0 ]; then
+    if [ "$ERROR" = 0 ]; then
         ok "$PACKAGE is configured"
 
     fi
diff --git a/bin/hardening/1.7.1.1_remove_os_info_motd.sh b/bin/hardening/1.7.1.1_remove_os_info_motd.sh
index 29ee794..87540da 100755
--- a/bin/hardening/1.7.1.1_remove_os_info_motd.sh
+++ b/bin/hardening/1.7.1.1_remove_os_info_motd.sh
@@ -22,7 +22,7 @@ PATTERN='(\\v|\\r|\\m|\\s)'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_pattern_exist_in_file $FILE "$PATTERN"
+    does_pattern_exist_in_file "$FILE" "$PATTERN"
     if [ "$FNRET" = 0 ]; then
         crit "$PATTERN is present in $FILE"
     else
@@ -32,10 +32,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_pattern_exist_in_file $FILE "$PATTERN"
+    does_pattern_exist_in_file "$FILE" "$PATTERN"
     if [ "$FNRET" = 0 ]; then
         warn "$PATTERN is present in $FILE"
-        delete_line_in_file $FILE $PATTERN
+        delete_line_in_file "$FILE" "$PATTERN"
     else
         ok "$PATTERN is not present in $FILE"
     fi
diff --git a/bin/hardening/1.7.1.2_remove_os_info_issue.sh b/bin/hardening/1.7.1.2_remove_os_info_issue.sh
index 2960586..c055301 100755
--- a/bin/hardening/1.7.1.2_remove_os_info_issue.sh
+++ b/bin/hardening/1.7.1.2_remove_os_info_issue.sh
@@ -22,7 +22,7 @@ PATTERN='(\\v|\\r|\\m|\\s)'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_pattern_exist_in_file $FILE "$PATTERN"
+    does_pattern_exist_in_file "$FILE" "$PATTERN"
     if [ "$FNRET" = 0 ]; then
         crit "$PATTERN is present in $FILE"
     else
@@ -35,7 +35,7 @@ apply() {
     does_pattern_exist_in_file $FILE "$PATTERN"
     if [ "$FNRET" = 0 ]; then
         warn "$PATTERN is present in $FILE"
-        delete_line_in_file $FILE $PATTERN
+        delete_line_in_file "$FILE" "$PATTERN"
     else
         ok "$PATTERN is not present in $FILE"
     fi
diff --git a/bin/hardening/1.7.1.3_remove_os_info_issue_net.sh b/bin/hardening/1.7.1.3_remove_os_info_issue_net.sh
index 7bc785c..381d0cf 100755
--- a/bin/hardening/1.7.1.3_remove_os_info_issue_net.sh
+++ b/bin/hardening/1.7.1.3_remove_os_info_issue_net.sh
@@ -22,7 +22,7 @@ PATTERN='(\\v|\\r|\\m|\\s)'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_pattern_exist_in_file $FILE "$PATTERN"
+    does_pattern_exist_in_file "$FILE" "$PATTERN"
     if [ "$FNRET" = 0 ]; then
         crit "$PATTERN is present in $FILE"
     else
@@ -32,10 +32,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_pattern_exist_in_file $FILE "$PATTERN"
+    does_pattern_exist_in_file "$FILE" "$PATTERN"
     if [ "$FNRET" = 0 ]; then
         warn "$PATTERN is present in $FILE"
-        delete_line_in_file $FILE $PATTERN
+        delete_line_in_file "$FILE" "$PATTERN"
     else
         ok "$PATTERN is not present in $FILE"
     fi
diff --git a/bin/hardening/1.7.1.4_motd_perms.sh b/bin/hardening/1.7.1.4_motd_perms.sh
index 20c117d..b697ad6 100755
--- a/bin/hardening/1.7.1.4_motd_perms.sh
+++ b/bin/hardening/1.7.1.4_motd_perms.sh
@@ -24,7 +24,7 @@ FILE='/etc/motd'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         crit "$FILE does not exist"
     else
@@ -45,10 +45,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         info "$FILE does not exist"
-        touch $FILE
+        touch "$FILE"
     fi
     has_file_correct_ownership "$FILE" "$USER" "$GROUP"
     if [ "$FNRET" = 0 ]; then
diff --git a/bin/hardening/1.7.1.5_etc_issue_perms.sh b/bin/hardening/1.7.1.5_etc_issue_perms.sh
index c103a4c..648da80 100755
--- a/bin/hardening/1.7.1.5_etc_issue_perms.sh
+++ b/bin/hardening/1.7.1.5_etc_issue_perms.sh
@@ -24,7 +24,7 @@ FILE='/etc/issue'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         crit "$FILE does not exist"
     else
@@ -45,10 +45,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         info "$FILE does not exist"
-        touch $FILE
+        touch "$FILE"
     fi
     has_file_correct_ownership "$FILE" "$USER" "$GROUP"
     if [ "$FNRET" = 0 ]; then
diff --git a/bin/hardening/1.7.1.6_etc_issue_net_perms.sh b/bin/hardening/1.7.1.6_etc_issue_net_perms.sh
index 74f321d..fd6aa7a 100755
--- a/bin/hardening/1.7.1.6_etc_issue_net_perms.sh
+++ b/bin/hardening/1.7.1.6_etc_issue_net_perms.sh
@@ -24,7 +24,7 @@ FILE='/etc/issue.net'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         crit "$FILE does not exist"
     else
@@ -45,10 +45,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         info "$FILE does not exist"
-        touch $FILE
+        touch "$FILE"
     fi
     has_file_correct_ownership "$FILE" "$USER" "$GROUP"
     if [ "$FNRET" = 0 ]; then
diff --git a/bin/hardening/2.2.1.2_configure_ntp.sh b/bin/hardening/2.2.1.2_configure_ntp.sh
index f718805..98aca64 100755
--- a/bin/hardening/2.2.1.2_configure_ntp.sh
+++ b/bin/hardening/2.2.1.2_configure_ntp.sh
@@ -60,16 +60,16 @@ apply() {
     does_pattern_exist_in_file "$NTP_CONF_FILE" "$NTP_CONF_DEFAULT_PATTERN"
     if [ "$FNRET" != 0 ]; then
         warn "$NTP_CONF_DEFAULT_PATTERN not found in $NTP_CONF_FILE, adding it"
-        backup_file $NTP_CONF_FILE
-        add_end_of_file $NTP_CONF_FILE "restrict -4 default kod notrap nomodify nopeer noquery"
+        backup_file "$NTP_CONF_FILE"
+        add_end_of_file "$NTP_CONF_FILE" "restrict -4 default kod notrap nomodify nopeer noquery"
     else
         ok "$NTP_CONF_DEFAULT_PATTERN found in $NTP_CONF_FILE"
     fi
-    does_pattern_exist_in_file $NTP_INIT_FILE "^$NTP_INIT_PATTERN"
+    does_pattern_exist_in_file "$NTP_INIT_FILE" "^$NTP_INIT_PATTERN"
     if [ "$FNRET" != 0 ]; then
         warn "$NTP_INIT_PATTERN not found in $NTP_INIT_FILE, adding it"
-        backup_file $NTP_INIT_FILE
-        add_line_file_before_pattern $NTP_INIT_FILE $NTP_INIT_PATTERN "^UGID"
+        backup_file "$NTP_INIT_FILE"
+        add_line_file_before_pattern "$NTP_INIT_FILE" "$NTP_INIT_PATTERN" "^UGID"
     else
         ok "$NTP_INIT_PATTERN found in $NTP_INIT_FILE"
     fi
diff --git a/bin/hardening/2.2.1.3_configure_chrony.sh b/bin/hardening/2.2.1.3_configure_chrony.sh
index c5bc8ee..ebaab56 100755
--- a/bin/hardening/2.2.1.3_configure_chrony.sh
+++ b/bin/hardening/2.2.1.3_configure_chrony.sh
@@ -30,7 +30,7 @@ audit() {
         crit "$PACKAGE is not installed!"
     else
         ok "$PACKAGE is installed, checking configuration"
-        does_pattern_exist_in_file $CONF_FILE $CONF_DEFAULT_PATTERN
+        does_pattern_exist_in_file "$CONF_FILE" "$CONF_DEFAULT_PATTERN"
         if [ "$FNRET" != 0 ]; then
             crit "$CONF_DEFAULT_PATTERN not found in $CONF_FILE"
         else
diff --git a/bin/hardening/2.2.12_disable_samba.sh b/bin/hardening/2.2.12_disable_samba.sh
index a015fff..940f0eb 100755
--- a/bin/hardening/2.2.12_disable_samba.sh
+++ b/bin/hardening/2.2.12_disable_samba.sh
@@ -32,7 +32,7 @@ audit() {
             ok "$PACKAGE is absent"
         fi
     done
-    is_service_enabled $SERVICE
+    is_service_enabled "$SERVICE"
     if [ "$FNRET" = 0 ]; then
         crit "Service $SERVICE is enabled!"
     else
@@ -52,10 +52,10 @@ apply() {
             ok "$PACKAGE is absent"
         fi
     done
-    is_service_enabled $SERVICE
+    is_service_enabled "$SERVICE"
     if [ "$FNRET" = 0 ]; then
         crit "Service $SERVICE is enabled!"
-        systemctl disable $SERVICE
+        systemctl disable "$SERVICE"
     else
         ok "Service $SERVICE is disabled"
     fi
diff --git a/bin/hardening/2.2.16_disable_rsync.sh b/bin/hardening/2.2.16_disable_rsync.sh
index 0019919..4d91f26 100755
--- a/bin/hardening/2.2.16_disable_rsync.sh
+++ b/bin/hardening/2.2.16_disable_rsync.sh
@@ -31,7 +31,7 @@ audit() {
         ok "$PACKAGE is not installed"
     else
         ok "$PACKAGE is installed, checking configuration"
-        does_pattern_exist_in_file $RSYNC_DEFAULT_FILE "^$RSYNC_DEFAULT_PATTERN"
+        does_pattern_exist_in_file "$RSYNC_DEFAULT_FILE" "^$RSYNC_DEFAULT_PATTERN"
         if [ "$FNRET" != 0 ]; then
             crit "$RSYNC_DEFAULT_PATTERN not found in $RSYNC_DEFAULT_FILE"
         else
@@ -47,11 +47,11 @@ apply() {
         ok "$PACKAGE is not installed"
     else
         ok "$PACKAGE is installed, checking configuration"
-        does_pattern_exist_in_file $RSYNC_DEFAULT_FILE "^$RSYNC_DEFAULT_PATTERN"
+        does_pattern_exist_in_file "$RSYNC_DEFAULT_FILE" "^$RSYNC_DEFAULT_PATTERN"
         if [ "$FNRET" != 0 ]; then
             warn "$RSYNC_DEFAULT_PATTERN not found in $RSYNC_DEFAULT_FILE, adding it"
-            backup_file $RSYNC_DEFAULT_FILE
-            replace_in_file $RSYNC_DEFAULT_FILE $RSYNC_DEFAULT_PATTERN_TO_SEARCH $RSYNC_DEFAULT_PATTERN
+            backup_file "$RSYNC_DEFAULT_FILE"
+            replace_in_file "$RSYNC_DEFAULT_FILE" "$RSYNC_DEFAULT_PATTERN_TO_SEARCH" "$RSYNC_DEFAULT_PATTERN"
         else
             ok "$RSYNC_DEFAULT_PATTERN found in $RSYNC_DEFAULT_FILE"
         fi
diff --git a/bin/hardening/2.2.18_disable_telnet_server.sh b/bin/hardening/2.2.18_disable_telnet_server.sh
index 3fd3856..646695c 100755
--- a/bin/hardening/2.2.18_disable_telnet_server.sh
+++ b/bin/hardening/2.2.18_disable_telnet_server.sh
@@ -30,11 +30,11 @@ audit() {
         is_pkg_installed "$PACKAGE"
         if [ "$FNRET" = 0 ]; then
             warn "$PACKAGE is installed, checking configuration"
-            does_file_exist $FILE
+            does_file_exist "$FILE"
             if [ "$FNRET" != 0 ]; then
                 ok "$FILE does not exist"
             else
-                does_pattern_exist_in_file $FILE $PATTERN
+                does_pattern_exist_in_file "$FILE" "$PATTERN"
                 if [ "$FNRET" = 0 ]; then
                     crit "$PATTERN exists, $PACKAGE services are enabled!"
                 else
@@ -58,18 +58,18 @@ apply() {
         else
             ok "$PACKAGE is absent"
         fi
-        does_file_exist $FILE
+        does_file_exist "$FILE"
         if [ "$FNRET" != 0 ]; then
             ok "$FILE does not exist"
         else
             info "$FILE exists, checking patterns"
-            does_pattern_exist_in_file $FILE $PATTERN
+            does_pattern_exist_in_file "$FILE" "$PATTERN"
             if [ "$FNRET" = 0 ]; then
                 warn "$PATTERN is present in $FILE, purging it"
                 backup_file $FILE
                 # shellcheck disable=SC2001
                 ESCAPED_PATTERN=$(sed "s/|\|(\|)/\\\&/g" <<<$PATTERN)
-                sed -ie "s/$ESCAPED_PATTERN/#&/g" $FILE
+                sed -ie "s/$ESCAPED_PATTERN/#&/g" "$FILE"
             else
                 ok "$PATTERN is not present in $FILE"
             fi
diff --git a/bin/hardening/3.2.2_disable_icmp_redirect.sh b/bin/hardening/3.2.2_disable_icmp_redirect.sh
index 35f4770..e6dcc17 100755
--- a/bin/hardening/3.2.2_disable_icmp_redirect.sh
+++ b/bin/hardening/3.2.2_disable_icmp_redirect.sh
@@ -23,7 +23,7 @@ SYSCTL_PARAMS=''
 audit() {
     for SYSCTL_VALUES in $SYSCTL_PARAMS; do
         does_sysctl_param_exists "net.ipv6"
-        if [ "$FNRET" = 0 ] || [[ ! $SYSCTL_VALUES =~ .*ipv6.* ]]; then # IPv6 is enabled or SYSCTL_VALUES doesn't contain ipv6
+        if [ "$FNRET" = 0 ] || [[ ! "$SYSCTL_VALUES" =~ .*ipv6.* ]]; then # IPv6 is enabled or SYSCTL_VALUES doesn't contain ipv6
             SYSCTL_PARAM=$(echo "$SYSCTL_VALUES" | cut -d= -f 1)
             SYSCTL_EXP_RESULT=$(echo "$SYSCTL_VALUES" | cut -d= -f 2)
             debug "$SYSCTL_PARAM should be set to $SYSCTL_EXP_RESULT"
diff --git a/bin/hardening/3.2.6_enable_bad_error_message_protection.sh b/bin/hardening/3.2.6_enable_bad_error_message_protection.sh
index 9de2801..8f451a2 100755
--- a/bin/hardening/3.2.6_enable_bad_error_message_protection.sh
+++ b/bin/hardening/3.2.6_enable_bad_error_message_protection.sh
@@ -39,8 +39,8 @@ audit() {
 # This function will be called if the script status is on enabled mode
 apply() {
     for SYSCTL_VALUES in $SYSCTL_PARAMS; do
-        SYSCTL_PARAM=$(echo $SYSCTL_VALUES | cut -d= -f 1)
-        SYSCTL_EXP_RESULT=$(echo $SYSCTL_VALUES | cut -d= -f 2)
+        SYSCTL_PARAM=$(echo "$SYSCTL_VALUES" | cut -d= -f 1)
+        SYSCTL_EXP_RESULT=$(echo "$SYSCTL_VALUES" | cut -d= -f 2)
         debug "$SYSCTL_PARAM should be set to $SYSCTL_EXP_RESULT"
         has_sysctl_param_expected_result "$SYSCTL_PARAM" "$SYSCTL_EXP_RESULT"
         if [ "$FNRET" != 0 ]; then
diff --git a/bin/hardening/3.2.8_enable_tcp_syn_cookies.sh b/bin/hardening/3.2.8_enable_tcp_syn_cookies.sh
index e6cbd2d..37db31c 100755
--- a/bin/hardening/3.2.8_enable_tcp_syn_cookies.sh
+++ b/bin/hardening/3.2.8_enable_tcp_syn_cookies.sh
@@ -39,8 +39,8 @@ audit() {
 # This function will be called if the script status is on enabled mode
 apply() {
     for SYSCTL_VALUES in $SYSCTL_PARAMS; do
-        SYSCTL_PARAM=$(echo $SYSCTL_VALUES | cut -d= -f 1)
-        SYSCTL_EXP_RESULT=$(echo $SYSCTL_VALUES | cut -d= -f 2)
+        SYSCTL_PARAM=$(echo "$SYSCTL_VALUES" | cut -d= -f 1)
+        SYSCTL_EXP_RESULT=$(echo "$SYSCTL_VALUES" | cut -d= -f 2)
         debug "$SYSCTL_PARAM should be set to $SYSCTL_EXP_RESULT"
         has_sysctl_param_expected_result "$SYSCTL_PARAM" "$SYSCTL_EXP_RESULT"
         if [ "$FNRET" != 0 ]; then
diff --git a/bin/hardening/3.3.2_hosts_allow.sh b/bin/hardening/3.3.2_hosts_allow.sh
index c90e572..60291d9 100755
--- a/bin/hardening/3.3.2_hosts_allow.sh
+++ b/bin/hardening/3.3.2_hosts_allow.sh
@@ -21,7 +21,7 @@ FILE='/etc/hosts.allow'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         crit "$FILE does not exist"
     else
@@ -31,10 +31,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         warn "$FILE does not exist, creating it"
-        touch $FILE
+        touch "$FILE"
         warn "You may want to fill it with allowed networks"
     else
         ok "$FILE exist"
diff --git a/bin/hardening/3.3.3_hosts_deny.sh b/bin/hardening/3.3.3_hosts_deny.sh
index c7d4e0d..4e7cca9 100755
--- a/bin/hardening/3.3.3_hosts_deny.sh
+++ b/bin/hardening/3.3.3_hosts_deny.sh
@@ -22,12 +22,12 @@ PATTERN='ALL: ALL'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         crit "$FILE does not exist"
     else
         ok "$FILE exists, checking configuration"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" != 0 ]; then
             crit "$PATTERN is not present in $FILE, we have to deny everything"
         else
@@ -38,17 +38,17 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         warn "$FILE does not exist, creating it"
-        touch $FILE
+        touch "$FILE"
     else
         ok "$FILE exists"
     fi
-    does_pattern_exist_in_file $FILE "$PATTERN"
+    does_pattern_exist_in_file "$FILE" "$PATTERN"
     if [ "$FNRET" != 0 ]; then
         crit "$PATTERN is not present in $FILE, we have to deny everything"
-        add_end_of_file $FILE "$PATTERN"
+        add_end_of_file "$FILE" "$PATTERN"
         warn "YOU MAY HAVE CUT YOUR ACCESS, CHECK BEFORE DISCONNECTING"
     else
         ok "$PATTERN is present in $FILE"
diff --git a/bin/hardening/3.5.1.1_net_fw_default_policy_drop.sh b/bin/hardening/3.5.1.1_net_fw_default_policy_drop.sh
index 8b5033e..692ea10 100755
--- a/bin/hardening/3.5.1.1_net_fw_default_policy_drop.sh
+++ b/bin/hardening/3.5.1.1_net_fw_default_policy_drop.sh
@@ -27,17 +27,17 @@ audit() {
     if [ "$FNRET" != 0 ]; then
         crit "$PACKAGE is not installed!"
     else
-        ipt=$($SUDO_CMD $PACKAGE -nL 2>/dev/null || true)
-        if [[ -z $ipt ]]; then
+        ipt=$($SUDO_CMD "$PACKAGE" -nL 2>/dev/null || true)
+        if [[ -z "$ipt" ]]; then
             crit "Empty return from $PACKAGE command. Aborting..."
             return
         fi
         for chain in $FW_CHAINS; do
             regex="Chain $chain \(policy ([A-Z]+)\)"
             # previous line will capture actual policy
-            if [[ $ipt =~ $regex ]]; then
+            if [[ "$ipt" =~ $regex ]]; then
                 actual_policy=${BASH_REMATCH[1]}
-                if [[ $actual_policy = "$FW_POLICY" ]]; then
+                if [[ "$actual_policy" = "$FW_POLICY" ]]; then
                     ok "Policy correctly set to $FW_POLICY for chain $chain"
                 else
                     crit "Policy set to $actual_policy for chain $chain, should be ${FW_POLICY}."
diff --git a/bin/hardening/4.1.1.1_audit_log_storage.sh b/bin/hardening/4.1.1.1_audit_log_storage.sh
index 11ea04b..834fe11 100755
--- a/bin/hardening/4.1.1.1_audit_log_storage.sh
+++ b/bin/hardening/4.1.1.1_audit_log_storage.sh
@@ -23,12 +23,12 @@ VALUE=5
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         crit "$FILE does not exist"
     else
         ok "$FILE exists, checking configuration"
-        does_pattern_exist_in_file $FILE "^${PATTERN}[[:space:]]"
+        does_pattern_exist_in_file "$FILE" "^${PATTERN}[[:space:]]"
         if [ "$FNRET" != 0 ]; then
             crit "$PATTERN is not present in $FILE"
         else
@@ -39,17 +39,17 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         warn "$FILE does not exist, creating it"
         touch $FILE
     else
         ok "$FILE exists"
     fi
-    does_pattern_exist_in_file $FILE "^${PATTERN}[[:space:]]"
+    does_pattern_exist_in_file "$FILE" "^${PATTERN}[[:space:]]"
     if [ "$FNRET" != 0 ]; then
         warn "$PATTERN is not present in $FILE, adding it"
-        add_end_of_file $FILE "$PATTERN = $VALUE"
+        add_end_of_file "$FILE" "$PATTERN = $VALUE"
     else
         ok "$PATTERN is present in $FILE"
     fi
diff --git a/bin/hardening/4.1.1.2_halt_when_audit_log_full.sh b/bin/hardening/4.1.1.2_halt_when_audit_log_full.sh
index 354bb14..5e6d243 100755
--- a/bin/hardening/4.1.1.2_halt_when_audit_log_full.sh
+++ b/bin/hardening/4.1.1.2_halt_when_audit_log_full.sh
@@ -22,7 +22,7 @@ OPTIONS=''
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         crit "$FILE does not exist"
     else
@@ -44,7 +44,7 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         warn "$FILE does not exist, creating it"
         touch $FILE
@@ -56,7 +56,7 @@ apply() {
         AUDIT_VALUE=$(echo "$AUDIT_OPTION" | cut -d= -f 2)
         debug "$AUDIT_PARAM should be set to $AUDIT_VALUE"
         PATTERN="^${AUDIT_PARAM}[[:space:]]*=[[:space:]]*$AUDIT_VALUE"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" != 0 ]; then
             warn "$PATTERN is not present in $FILE, adding it"
             does_pattern_exist_in_file "$FILE" "^$AUDIT_PARAM"
diff --git a/bin/hardening/4.1.1.3_keep_all_audit_logs.sh b/bin/hardening/4.1.1.3_keep_all_audit_logs.sh
index 05aa261..002cd7a 100755
--- a/bin/hardening/4.1.1.3_keep_all_audit_logs.sh
+++ b/bin/hardening/4.1.1.3_keep_all_audit_logs.sh
@@ -22,17 +22,17 @@ OPTIONS='max_log_file_action=keep_logs'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         crit "$FILE does not exist"
     else
         ok "$FILE exists, checking configuration"
         for AUDIT_OPTION in $OPTIONS; do
-            AUDIT_PARAM=$(echo $AUDIT_OPTION | cut -d= -f 1)
-            AUDIT_VALUE=$(echo $AUDIT_OPTION | cut -d= -f 2)
+            AUDIT_PARAM=$(echo "$AUDIT_OPTION" | cut -d= -f 1)
+            AUDIT_VALUE=$(echo "$AUDIT_OPTION" | cut -d= -f 2)
             PATTERN="^${AUDIT_PARAM}[[:space:]]*=[[:space:]]*$AUDIT_VALUE"
             debug "$AUDIT_PARAM should be set to $AUDIT_VALUE"
-            does_pattern_exist_in_file $FILE "$PATTERN"
+            does_pattern_exist_in_file "$FILE" "$PATTERN"
             if [ "$FNRET" != 0 ]; then
                 crit "$PATTERN is not present in $FILE"
             else
@@ -44,7 +44,7 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         warn "$FILE does not exist, creating it"
         touch $FILE
@@ -52,20 +52,20 @@ apply() {
         ok "$FILE exists"
     fi
     for AUDIT_OPTION in $OPTIONS; do
-        AUDIT_PARAM=$(echo $AUDIT_OPTION | cut -d= -f 1)
-        AUDIT_VALUE=$(echo $AUDIT_OPTION | cut -d= -f 2)
+        AUDIT_PARAM=$(echo "$AUDIT_OPTION" | cut -d= -f 1)
+        AUDIT_VALUE=$(echo "$AUDIT_OPTION" | cut -d= -f 2)
         debug "$AUDIT_PARAM should be set to $AUDIT_VALUE"
         PATTERN="^${AUDIT_PARAM}[[:space:]]*=[[:space:]]*$AUDIT_VALUE"
         does_pattern_exist_in_file $FILE "$PATTERN"
         if [ "$FNRET" != 0 ]; then
             warn "$PATTERN is not present in $FILE, adding it"
-            does_pattern_exist_in_file $FILE "^$AUDIT_PARAM"
+            does_pattern_exist_in_file "$FILE" "^$AUDIT_PARAM"
             if [ "$FNRET" != 0 ]; then
                 info "Parameter $AUDIT_PARAM seems absent from $FILE, adding at the end"
-                add_end_of_file $FILE "$AUDIT_PARAM = $AUDIT_VALUE"
+                add_end_of_file "$FILE" "$AUDIT_PARAM = $AUDIT_VALUE"
             else
                 info "Parameter $AUDIT_PARAM is present but with the wrong value -- Fixing"
-                replace_in_file $FILE "^${AUDIT_PARAM}[[:space:]]*=.*" "$AUDIT_PARAM = $AUDIT_VALUE"
+                replace_in_file "$FILE" "^${AUDIT_PARAM}[[:space:]]*=.*" "$AUDIT_PARAM = $AUDIT_VALUE"
             fi
         else
             ok "$PATTERN is present in $FILE"
diff --git a/bin/hardening/4.1.2_enable_auditd.sh b/bin/hardening/4.1.2_enable_auditd.sh
index 87bf2b9..1b226e2 100755
--- a/bin/hardening/4.1.2_enable_auditd.sh
+++ b/bin/hardening/4.1.2_enable_auditd.sh
@@ -50,8 +50,8 @@ apply() {
         ok "$SERVICE_NAME is enabled"
     else
         warn "$SERVICE_NAME is not enabled, enabling it"
-        update-rc.d $SERVICE_NAME remove >/dev/null 2>&1
-        update-rc.d $SERVICE_NAME defaults >/dev/null 2>&1
+        update-rc.d "$SERVICE_NAME" remove >/dev/null 2>&1
+        update-rc.d "$SERVICE_NAME" defaults >/dev/null 2>&1
     fi
 }
 
diff --git a/bin/hardening/4.1.3_audit_bootloader.sh b/bin/hardening/4.1.3_audit_bootloader.sh
index eefb27e..44e30cc 100755
--- a/bin/hardening/4.1.3_audit_bootloader.sh
+++ b/bin/hardening/4.1.3_audit_bootloader.sh
@@ -22,7 +22,7 @@ OPTIONS='GRUB_CMDLINE_LINUX="audit=1"'
 
 # This function will be called if the script status is on enabled / audit mode
 audit() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         crit "$FILE does not exist"
     else
@@ -44,7 +44,7 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         warn "$FILE does not exist, creating it"
         touch "$FILE"
diff --git a/bin/hardening/4.2.2.1_enable_syslog-ng.sh b/bin/hardening/4.2.2.1_enable_syslog-ng.sh
index b172f67..7fe0dfe 100755
--- a/bin/hardening/4.2.2.1_enable_syslog-ng.sh
+++ b/bin/hardening/4.2.2.1_enable_syslog-ng.sh
@@ -36,8 +36,8 @@ apply() {
     is_service_enabled "$SERVICE_NAME"
     if [ "$FNRET" != 0 ]; then
         info "Enabling $SERVICE_NAME"
-        update-rc.d $SERVICE_NAME remove >/dev/null 2>&1
-        update-rc.d $SERVICE_NAME defaults >/dev/null 2>&1
+        update-rc.d "$SERVICE_NAME" remove >/dev/null 2>&1
+        update-rc.d "$SERVICE_NAME" defaults >/dev/null 2>&1
     else
         ok "$SERVICE_NAME is enabled"
     fi
diff --git a/bin/hardening/4.2.2.4_syslog-ng_remote_host.sh b/bin/hardening/4.2.2.4_syslog-ng_remote_host.sh
index a5739f7..6881a61 100755
--- a/bin/hardening/4.2.2.4_syslog-ng_remote_host.sh
+++ b/bin/hardening/4.2.2.4_syslog-ng_remote_host.sh
@@ -22,7 +22,7 @@ PATTERN='destination[[:alnum:][:space:]*{]+(tcp|udp)[[:space:]]*\(\"[[:alnum:].]
 # This function will be called if the script status is on enabled / audit mode
 audit() {
     FOUND=0
-    FILES="$SYSLOG_BASEDIR/syslog-ng.conf $($SUDO_CMD find -L $SYSLOG_BASEDIR/conf.d/ -type f)"
+    FILES="$SYSLOG_BASEDIR/syslog-ng.conf $($SUDO_CMD find -L "$SYSLOG_BASEDIR"/conf.d/ -type f)"
     for FILE in $FILES; do
         does_pattern_exist_in_file_multiline "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
@@ -30,7 +30,7 @@ audit() {
         fi
     done
 
-    if [ $FOUND = 1 ]; then
+    if [ "$FOUND" = 1 ]; then
         ok "$PATTERN is present in $FILES"
     else
         crit "$PATTERN is not present in $FILES"
@@ -40,14 +40,14 @@ audit() {
 # This function will be called if the script status is on enabled mode
 apply() {
     FOUND=0
-    FILES="$SYSLOG_BASEDIR/syslog-ng.conf $(find -L $SYSLOG_BASEDIR/conf.d/ -type f)"
+    FILES="$SYSLOG_BASEDIR/syslog-ng.conf $(find -L "$SYSLOG_BASEDIR"/conf.d/ -type f)"
     for FILE in $FILES; do
         does_pattern_exist_in_file_multiline "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             FOUND=1
         fi
     done
-    if [ $FOUND = 1 ]; then
+    if [ "$FOUND" = 1 ]; then
         ok "$PATTERN is present in $FILES"
     else
         crit "$PATTERN is not present in $FILES, please set a remote host to send your logs"
diff --git a/bin/hardening/5.1.1_enable_cron.sh b/bin/hardening/5.1.1_enable_cron.sh
index 74ae378..bdd1f98 100755
--- a/bin/hardening/5.1.1_enable_cron.sh
+++ b/bin/hardening/5.1.1_enable_cron.sh
@@ -47,8 +47,8 @@ apply() {
         is_service_enabled "$SERVICE_NAME"
         if [ "$FNRET" != 0 ]; then
             info "Enabling $SERVICE_NAME"
-            update-rc.d $SERVICE_NAME remove >/dev/null 2>&1
-            update-rc.d $SERVICE_NAME defaults >/dev/null 2>&1
+            update-rc.d "$SERVICE_NAME" remove >/dev/null 2>&1
+            update-rc.d "$SERVICE_NAME" defaults >/dev/null 2>&1
         else
             ok "$SERVICE_NAME is enabled"
         fi
diff --git a/bin/hardening/5.1.2_crontab_perm_ownership.sh b/bin/hardening/5.1.2_crontab_perm_ownership.sh
index 4693fe5..cde6cad 100755
--- a/bin/hardening/5.1.2_crontab_perm_ownership.sh
+++ b/bin/hardening/5.1.2_crontab_perm_ownership.sh
@@ -40,10 +40,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         info "$FILE does not exist"
-        touch $FILE
+        touch "$FILE"
     fi
     has_file_correct_ownership "$FILE" "$USER" "$GROUP"
     if [ "$FNRET" = 0 ]; then
@@ -63,12 +63,12 @@ apply() {
 
 # This function will check config parameters required
 check_config() {
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
diff --git a/bin/hardening/5.1.3_cron_hourly_perm_ownership.sh b/bin/hardening/5.1.3_cron_hourly_perm_ownership.sh
index 28b5d5f..d66779a 100755
--- a/bin/hardening/5.1.3_cron_hourly_perm_ownership.sh
+++ b/bin/hardening/5.1.3_cron_hourly_perm_ownership.sh
@@ -40,10 +40,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         info "$FILE does not exist"
-        touch $FILE
+        touch "$FILE"
     fi
     has_file_correct_ownership "$FILE" "$USER" "$GROUP"
     if [ "$FNRET" = 0 ]; then
@@ -63,12 +63,12 @@ apply() {
 
 # This function will check config parameters required
 check_config() {
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
diff --git a/bin/hardening/5.1.4_cron_daily_perm_ownership.sh b/bin/hardening/5.1.4_cron_daily_perm_ownership.sh
index f2665af..8bc79a7 100755
--- a/bin/hardening/5.1.4_cron_daily_perm_ownership.sh
+++ b/bin/hardening/5.1.4_cron_daily_perm_ownership.sh
@@ -40,10 +40,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         info "$FILE does not exist"
-        touch $FILE
+        touch "$FILE"
     fi
     has_file_correct_ownership "$FILE" "$USER" "$GROUP"
     if [ "$FNRET" = 0 ]; then
@@ -63,12 +63,12 @@ apply() {
 
 # This function will check config parameters required
 check_config() {
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
diff --git a/bin/hardening/5.1.5_cron_weekly_perm_ownership.sh b/bin/hardening/5.1.5_cron_weekly_perm_ownership.sh
index dad3f52..425cb06 100755
--- a/bin/hardening/5.1.5_cron_weekly_perm_ownership.sh
+++ b/bin/hardening/5.1.5_cron_weekly_perm_ownership.sh
@@ -40,10 +40,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         info "$FILE does not exist"
-        touch $FILE
+        touch "$FILE"
     fi
     has_file_correct_ownership "$FILE" "$USER" "$GROUP"
     if [ "$FNRET" = 0 ]; then
@@ -63,12 +63,12 @@ apply() {
 
 # This function will check config parameters required
 check_config() {
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
diff --git a/bin/hardening/5.1.6_cron_monthly_perm_ownership.sh b/bin/hardening/5.1.6_cron_monthly_perm_ownership.sh
index 6f1bae9..0462153 100755
--- a/bin/hardening/5.1.6_cron_monthly_perm_ownership.sh
+++ b/bin/hardening/5.1.6_cron_monthly_perm_ownership.sh
@@ -40,10 +40,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         info "$FILE does not exist"
-        touch $FILE
+        touch "$FILE"
     fi
     has_file_correct_ownership "$FILE" "$USER" "$GROUP"
     if [ "$FNRET" = 0 ]; then
@@ -63,12 +63,12 @@ apply() {
 
 # This function will check config parameters required
 check_config() {
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
diff --git a/bin/hardening/5.1.7_cron_d_perm_ownership.sh b/bin/hardening/5.1.7_cron_d_perm_ownership.sh
index ad74f4b..36334b3 100755
--- a/bin/hardening/5.1.7_cron_d_perm_ownership.sh
+++ b/bin/hardening/5.1.7_cron_d_perm_ownership.sh
@@ -40,10 +40,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         info "$FILE does not exist"
-        touch $FILE
+        touch "$FILE"
     fi
     has_file_correct_ownership "$FILE" "$USER" "$GROUP"
     if [ "$FNRET" = 0 ]; then
@@ -63,12 +63,12 @@ apply() {
 
 # This function will check config parameters required
 check_config() {
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
diff --git a/bin/hardening/5.1.8_cron_users.sh b/bin/hardening/5.1.8_cron_users.sh
index ad3f1b6..64723df 100755
--- a/bin/hardening/5.1.8_cron_users.sh
+++ b/bin/hardening/5.1.8_cron_users.sh
@@ -90,12 +90,12 @@ apply() {
 
 # This function will check config parameters required
 check_config() {
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
diff --git a/bin/hardening/5.2.10_disable_root_login.sh b/bin/hardening/5.2.10_disable_root_login.sh
index 7c02be7..48b08b9 100755
--- a/bin/hardening/5.2.10_disable_root_login.sh
+++ b/bin/hardening/5.2.10_disable_root_login.sh
@@ -55,7 +55,7 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.2.12_disable_sshd_setenv.sh b/bin/hardening/5.2.12_disable_sshd_setenv.sh
index ff237f1..0eed930 100755
--- a/bin/hardening/5.2.12_disable_sshd_setenv.sh
+++ b/bin/hardening/5.2.12_disable_sshd_setenv.sh
@@ -60,7 +60,7 @@ apply() {
             ok "$PATTERN is present in $FILE"
         else
             warn "$PATTERN is not present in $FILE, adding it"
-            does_pattern_exist_in_file $FILE "^${SSH_PARAM}"
+            does_pattern_exist_in_file "$FILE" "^${SSH_PARAM}"
             if [ "$FNRET" != 0 ]; then
                 add_end_of_file "$FILE" "$SSH_PARAM $SSH_VALUE"
             else
diff --git a/bin/hardening/5.2.13_sshd_ciphers.sh b/bin/hardening/5.2.13_sshd_ciphers.sh
index 9564456..3134a72 100755
--- a/bin/hardening/5.2.13_sshd_ciphers.sh
+++ b/bin/hardening/5.2.13_sshd_ciphers.sh
@@ -55,7 +55,7 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.2.14_ssh_cry_mac.sh b/bin/hardening/5.2.14_ssh_cry_mac.sh
index e6d8537..0a8e431 100755
--- a/bin/hardening/5.2.14_ssh_cry_mac.sh
+++ b/bin/hardening/5.2.14_ssh_cry_mac.sh
@@ -55,7 +55,7 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+        does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.2.15_ssh_cry_kex.sh b/bin/hardening/5.2.15_ssh_cry_kex.sh
index 72eb636..e77f960 100755
--- a/bin/hardening/5.2.15_ssh_cry_kex.sh
+++ b/bin/hardening/5.2.15_ssh_cry_kex.sh
@@ -55,7 +55,7 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+        does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.2.18_sshd_limit_access.sh b/bin/hardening/5.2.18_sshd_limit_access.sh
index 160cc3f..b843dde 100755
--- a/bin/hardening/5.2.18_sshd_limit_access.sh
+++ b/bin/hardening/5.2.18_sshd_limit_access.sh
@@ -34,7 +34,7 @@ audit() {
             # shellcheck disable=SC2001
             SSH_VALUE=$(sed "s/'//g" <<<"$SSH_VALUE")
             PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-            does_pattern_exist_in_file $FILE "$PATTERN"
+            does_pattern_exist_in_file "$FILE" "$PATTERN"
             if [ "$FNRET" = 0 ]; then
                 ok "$PATTERN is present in $FILE"
             else
diff --git a/bin/hardening/5.2.19_ssh_banner.sh b/bin/hardening/5.2.19_ssh_banner.sh
index 3a50778..5822514 100755
--- a/bin/hardening/5.2.19_ssh_banner.sh
+++ b/bin/hardening/5.2.19_ssh_banner.sh
@@ -31,7 +31,7 @@ audit() {
         for SSH_OPTION in $OPTIONS; do
             SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
             PATTERN="^${SSH_PARAM}[[:space:]]*"
-            does_pattern_exist_in_file $FILE "$PATTERN"
+            does_pattern_exist_in_file "$FILE" "$PATTERN"
             if [ "$FNRET" = 0 ]; then
                 ok "$PATTERN is present in $FILE"
             else
@@ -54,7 +54,7 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.2.1_sshd_conf_perm_ownership.sh b/bin/hardening/5.2.1_sshd_conf_perm_ownership.sh
index ae08dc8..dde8f11 100755
--- a/bin/hardening/5.2.1_sshd_conf_perm_ownership.sh
+++ b/bin/hardening/5.2.1_sshd_conf_perm_ownership.sh
@@ -40,10 +40,10 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_file_exist $FILE
+    does_file_exist "$FILE"
     if [ "$FNRET" != 0 ]; then
         info "$FILE does not exist"
-        touch $FILE
+        touch "$FILE"
     fi
     has_file_correct_ownership "$FILE" "$USER" "$GROUP"
     if [ "$FNRET" = 0 ]; then
@@ -63,12 +63,12 @@ apply() {
 
 # This function will check config parameters required
 check_config() {
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
diff --git a/bin/hardening/5.2.2_ssh_host_private_keys_perm_ownership.sh b/bin/hardening/5.2.2_ssh_host_private_keys_perm_ownership.sh
index e38ca42..3285791 100755
--- a/bin/hardening/5.2.2_ssh_host_private_keys_perm_ownership.sh
+++ b/bin/hardening/5.2.2_ssh_host_private_keys_perm_ownership.sh
@@ -83,12 +83,12 @@ apply() {
 
 # This function will check config parameters required
 check_config() {
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
diff --git a/bin/hardening/5.2.3_ssh_host_public_keys_perm_ownership.sh b/bin/hardening/5.2.3_ssh_host_public_keys_perm_ownership.sh
index 446ce9f..bef6154 100755
--- a/bin/hardening/5.2.3_ssh_host_public_keys_perm_ownership.sh
+++ b/bin/hardening/5.2.3_ssh_host_public_keys_perm_ownership.sh
@@ -103,12 +103,12 @@ apply() {
 
 # This function will check config parameters required
 check_config() {
-    does_user_exist $USER
+    does_user_exist "$USER"
     if [ "$FNRET" != 0 ]; then
         crit "$USER does not exist"
         exit 128
     fi
-    does_group_exist $GROUP
+    does_group_exist "$GROUP"
     if [ "$FNRET" != 0 ]; then
         crit "$GROUP does not exist"
         exit 128
diff --git a/bin/hardening/5.2.5_sshd_loglevel.sh b/bin/hardening/5.2.5_sshd_loglevel.sh
index a69c62a..b6d2a4f 100755
--- a/bin/hardening/5.2.5_sshd_loglevel.sh
+++ b/bin/hardening/5.2.5_sshd_loglevel.sh
@@ -56,7 +56,7 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+        does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.2.6_disable_x11_forwarding.sh b/bin/hardening/5.2.6_disable_x11_forwarding.sh
index a26dfde..5c262bf 100755
--- a/bin/hardening/5.2.6_disable_x11_forwarding.sh
+++ b/bin/hardening/5.2.6_disable_x11_forwarding.sh
@@ -55,7 +55,7 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.2.7_sshd_maxauthtries.sh b/bin/hardening/5.2.7_sshd_maxauthtries.sh
index a56c699..a5b1c8a 100755
--- a/bin/hardening/5.2.7_sshd_maxauthtries.sh
+++ b/bin/hardening/5.2.7_sshd_maxauthtries.sh
@@ -55,7 +55,7 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.2.8_enable_sshd_ignorerhosts.sh b/bin/hardening/5.2.8_enable_sshd_ignorerhosts.sh
index 97654fc..bdbcfd1 100755
--- a/bin/hardening/5.2.8_enable_sshd_ignorerhosts.sh
+++ b/bin/hardening/5.2.8_enable_sshd_ignorerhosts.sh
@@ -55,7 +55,7 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.2.9_disable_sshd_hostbasedauthentication.sh b/bin/hardening/5.2.9_disable_sshd_hostbasedauthentication.sh
index 5495680..96a8b1b 100755
--- a/bin/hardening/5.2.9_disable_sshd_hostbasedauthentication.sh
+++ b/bin/hardening/5.2.9_disable_sshd_hostbasedauthentication.sh
@@ -55,7 +55,7 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.3.1_enable_pwquality.sh b/bin/hardening/5.3.1_enable_pwquality.sh
index 2099dff..d966cc8 100755
--- a/bin/hardening/5.3.1_enable_pwquality.sh
+++ b/bin/hardening/5.3.1_enable_pwquality.sh
@@ -67,7 +67,7 @@ apply() {
         ok "$PATTERN_COMMON is present in $FILE_COMMON"
     else
         warn "$PATTERN_COMMON is not present in $FILE_COMMON"
-        add_line_file_before_pattern $FILE_COMMON "password requisite pam_pwquality.so retry=3" "# pam-auth-update(8) for details."
+        add_line_file_before_pattern "$FILE_COMMON" "password requisite pam_pwquality.so retry=3" "# pam-auth-update(8) for details."
     fi
 
     for PW_OPT in $OPTIONS; do
diff --git a/bin/hardening/5.3.2_enable_lockout_failed_password.sh b/bin/hardening/5.3.2_enable_lockout_failed_password.sh
index d832091..9c9f2b2 100755
--- a/bin/hardening/5.3.2_enable_lockout_failed_password.sh
+++ b/bin/hardening/5.3.2_enable_lockout_failed_password.sh
@@ -30,13 +30,13 @@ audit() {
         crit "$PACKAGE is not installed!"
     else
         ok "$PACKAGE is installed"
-        does_pattern_exist_in_file $FILE_AUTH "$PATTERN_AUTH"
+        does_pattern_exist_in_file "$FILE_AUTH" "$PATTERN_AUTH"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN_AUTH is present in $FILE_AUTH"
         else
             crit "$PATTERN_AUTH is not present in $FILE_AUTH"
         fi
-        does_pattern_exist_in_file $FILE_ACCOUNT "$PATTERN_ACCOUNT"
+        does_pattern_exist_in_file "$FILE_ACCOUNT" "$PATTERN_ACCOUNT"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN_ACCOUNT is present in $FILE_ACCOUNT"
         else
@@ -54,19 +54,19 @@ apply() {
         crit "$PACKAGE is absent, installing it"
         apt_install "$PACKAGE"
     fi
-    does_pattern_exist_in_file $FILE_AUTH "$PATTERN_AUTH"
+    does_pattern_exist_in_file "$FILE_AUTH" "$PATTERN_AUTH"
     if [ "$FNRET" = 0 ]; then
         ok "$PATTERN_AUTH is present in $FILE_AUTH"
     else
         warn "$PATTERN_AUTH is not present in $FILE_AUTH, adding it"
-        add_line_file_before_pattern $FILE_AUTH "auth required pam_tally2.so onerr=fail audit silent deny=5 unlock_time=900" "# pam-auth-update(8) for details."
+        add_line_file_before_pattern "$FILE_AUTH" "auth required pam_tally2.so onerr=fail audit silent deny=5 unlock_time=900" "# pam-auth-update(8) for details."
     fi
-    does_pattern_exist_in_file $FILE_ACCOUNT "$PATTERN_ACCOUNT"
+    does_pattern_exist_in_file "$FILE_ACCOUNT" "$PATTERN_ACCOUNT"
     if [ "$FNRET" = 0 ]; then
         ok "$PATTERN_ACCOUNT is present in $FILE_ACCOUNT"
     else
         warn "$PATTERN_ACCOUNT is not present in $FILE_ACCOUNT, adding it"
-        add_line_file_before_pattern $FILE_ACCOUNT "account required pam_tally.so" "# pam-auth-update(8) for details."
+        add_line_file_before_pattern "$FILE_ACCOUNT" "account required pam_tally.so" "# pam-auth-update(8) for details."
 
     fi
 }
diff --git a/bin/hardening/5.3.3_limit_password_reuse.sh b/bin/hardening/5.3.3_limit_password_reuse.sh
index e1eb350..3845db7 100755
--- a/bin/hardening/5.3.3_limit_password_reuse.sh
+++ b/bin/hardening/5.3.3_limit_password_reuse.sh
@@ -28,7 +28,7 @@ audit() {
         crit "$PACKAGE is not installed!"
     else
         ok "$PACKAGE is installed"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
@@ -46,12 +46,12 @@ apply() {
         crit "$PACKAGE is absent, installing it"
         apt_install "$PACKAGE"
     fi
-    does_pattern_exist_in_file $FILE "$PATTERN"
+    does_pattern_exist_in_file "$FILE" "$PATTERN"
     if [ "$FNRET" = 0 ]; then
         ok "$PATTERN is present in $FILE"
     else
         warn "$PATTERN is not present in $FILE, adding it"
-        add_line_file_before_pattern $FILE "password [success=1 default=ignore] pam_unix.so obscure sha512 remember=5" "# pam-auth-update(8) for details."
+        add_line_file_before_pattern "$FILE" "password [success=1 default=ignore] pam_unix.so obscure sha512 remember=5" "# pam-auth-update(8) for details."
     fi
 }
 
diff --git a/bin/hardening/5.3.4_acc_pam_sha512.sh b/bin/hardening/5.3.4_acc_pam_sha512.sh
index ec86c89..c7e31f2 100755
--- a/bin/hardening/5.3.4_acc_pam_sha512.sh
+++ b/bin/hardening/5.3.4_acc_pam_sha512.sh
@@ -21,11 +21,11 @@ CONF_LINE="^\s*password\s.+\s+pam_unix\.so\s+.*sha512"
 # This function will be called if the script status is on enabled / audit mode
 audit() {
     # Check conf file for default SHA512 hash
-    if $SUDO_CMD [ ! -r $CONF_FILE ]; then
+    if $SUDO_CMD [ ! -r "$CONF_FILE" ]; then
         crit "$CONF_FILE is not readable"
     else
         # shellcheck disable=SC2001
-        does_pattern_exist_in_file $CONF_FILE "$(sed 's/ /[[:space:]]+/g' <<<"$CONF_LINE")"
+        does_pattern_exist_in_file "$CONF_FILE" "$(sed 's/ /[[:space:]]+/g' <<<"$CONF_LINE")"
         if [ "$FNRET" = 0 ]; then
             ok "$CONF_LINE is present in $CONF_FILE"
         else
@@ -36,16 +36,16 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    if $SUDO_CMD [ ! -r $CONF_FILE ]; then
+    if $SUDO_CMD [ ! -r "$CONF_FILE" ]; then
         crit "$CONF_FILE is not readable"
     else
         # shellcheck disable=SC2001
-        does_pattern_exist_in_file $CONF_FILE "$(sed 's/ /[[:space:]]+/g' <<<"$CONF_LINE")"
+        does_pattern_exist_in_file "$CONF_FILE" "$(sed 's/ /[[:space:]]+/g' <<<"$CONF_LINE")"
         if [ "$FNRET" = 0 ]; then
             ok "$CONF_LINE is present in $CONF_FILE"
         else
             warn "$CONF_LINE is not present in $CONF_FILE"
-            add_line_file_before_pattern $CONF_FILE "password [success=1 default=ignore] pam_unix.so sha512" "# pam-auth-update(8) for details."
+            add_line_file_before_pattern "$CONF_FILE" "password [success=1 default=ignore] pam_unix.so sha512" "# pam-auth-update(8) for details."
         fi
     fi
 }
diff --git a/bin/hardening/5.4.1.2_set_password_min_days_change.sh b/bin/hardening/5.4.1.2_set_password_min_days_change.sh
index 3c81992..378fa56 100755
--- a/bin/hardening/5.4.1.2_set_password_min_days_change.sh
+++ b/bin/hardening/5.4.1.2_set_password_min_days_change.sh
@@ -60,7 +60,7 @@ apply() {
             ok "$PATTERN is present in $FILE"
         else
             warn "$PATTERN is not present in $FILE, adding it"
-            does_pattern_exist_in_file $FILE "^${SHADOW_PARAM}"
+            does_pattern_exist_in_file "$FILE" "^${SHADOW_PARAM}"
             if [ "$FNRET" != 0 ]; then
                 add_end_of_file "$FILE" "$SHADOW_PARAM $SHADOW_VALUE"
             else
diff --git a/bin/hardening/5.4.1.3_set_password_exp_warning_days.sh b/bin/hardening/5.4.1.3_set_password_exp_warning_days.sh
index ab523ef..ab5631a 100755
--- a/bin/hardening/5.4.1.3_set_password_exp_warning_days.sh
+++ b/bin/hardening/5.4.1.3_set_password_exp_warning_days.sh
@@ -32,7 +32,7 @@ audit() {
             SHADOW_PARAM=$(echo "$SHADOW_OPTION" | cut -d= -f 1)
             SHADOW_VALUE=$(echo "$SHADOW_OPTION" | cut -d= -f 2)
             PATTERN="^${SHADOW_PARAM}[[:space:]]*$SHADOW_VALUE"
-            does_pattern_exist_in_file $FILE "$PATTERN"
+            does_pattern_exist_in_file "$FILE" "$PATTERN"
             if [ "$FNRET" = 0 ]; then
                 ok "$PATTERN is present in $FILE"
             else
@@ -55,7 +55,7 @@ apply() {
         SHADOW_PARAM=$(echo "$SHADOW_OPTION" | cut -d= -f 1)
         SHADOW_VALUE=$(echo "$SHADOW_OPTION" | cut -d= -f 2)
         PATTERN="^${SHADOW_PARAM}[[:space:]]*$SHADOW_VALUE"
-        does_pattern_exist_in_file $FILE "$PATTERN"
+        does_pattern_exist_in_file "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
diff --git a/bin/hardening/5.4.2_disable_system_accounts.sh b/bin/hardening/5.4.2_disable_system_accounts.sh
index 2aeb9b4..9fa9d79 100755
--- a/bin/hardening/5.4.2_disable_system_accounts.sh
+++ b/bin/hardening/5.4.2_disable_system_accounts.sh
@@ -27,7 +27,7 @@ ACCEPTED_SHELLS_GREP=''
 audit() {
     shells_to_grep_helper
     info "Checking if admin accounts have a login shell different than $ACCEPTED_SHELLS"
-    RESULT=$(grep -Ev "^\+" $FILE | awk -F: '($1!="root" && $1!="sync" && $1!="shutdown" && $1!="halt" && $3<1000 ) {print}' | grep -v $ACCEPTED_SHELLS_GREP || true)
+    RESULT=$(grep -Ev "^\+" "$FILE" | awk -F: '($1!="root" && $1!="sync" && $1!="shutdown" && $1!="halt" && $3<1000 ) {print}' | grep -v $ACCEPTED_SHELLS_GREP || true)
     IFS_BAK=$IFS
     IFS=$'\n'
     for LINE in $RESULT; do
@@ -55,7 +55,7 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    RESULT=$(grep -Ev "^\+" $FILE | awk -F: '($1!="root" && $1!="sync" && $1!="shutdown" && $1!="halt" && $3<1000 ) {print}' | grep -v $ACCEPTED_SHELLS_GREP || true)
+    RESULT=$(grep -Ev "^\+" "$FILE" | awk -F: '($1!="root" && $1!="sync" && $1!="shutdown" && $1!="halt" && $3<1000 ) {print}' | grep -v $ACCEPTED_SHELLS_GREP || true)
     IFS_BAK=$IFS
     IFS=$'\n'
     for LINE in $RESULT; do
diff --git a/bin/hardening/6.1.10_find_world_writable_file.sh b/bin/hardening/6.1.10_find_world_writable_file.sh
index 8fc1d0e..3221eaf 100755
--- a/bin/hardening/6.1.10_find_world_writable_file.sh
+++ b/bin/hardening/6.1.10_find_world_writable_file.sh
@@ -25,7 +25,7 @@ audit() {
     if [ -n "$RESULT" ]; then
         crit "Some world writable files are present"
         # shellcheck disable=SC2001
-        FORMATTED_RESULT=$(sed "s/ /\n/g" <<<$RESULT | sort | uniq | tr '\n' ' ')
+        FORMATTED_RESULT=$(sed "s/ /\n/g" <<<"$RESULT" | sort | uniq | tr '\n' ' ')
         crit "$FORMATTED_RESULT"
     else
         ok "No world writable files found"
diff --git a/bin/hardening/6.1.11_find_unowned_files.sh b/bin/hardening/6.1.11_find_unowned_files.sh
index 3f2d494..8dc73bf 100755
--- a/bin/hardening/6.1.11_find_unowned_files.sh
+++ b/bin/hardening/6.1.11_find_unowned_files.sh
@@ -32,7 +32,7 @@ audit() {
     if [ -n "$RESULT" ]; then
         crit "Some unowned files are present"
         # shellcheck disable=SC2001
-        FORMATTED_RESULT=$(sed "s/ /\n/g" <<<$RESULT | sort | uniq | tr '\n' ' ')
+        FORMATTED_RESULT=$(sed "s/ /\n/g" <<<"$RESULT" | sort | uniq | tr '\n' ' ')
         crit "$FORMATTED_RESULT"
     else
         ok "No unowned files found"
@@ -48,7 +48,7 @@ apply() {
     fi
     if [ -n "$RESULT" ]; then
         warn "Applying chown on all unowned files in the system"
-        df --local -P | awk '{if (NR!=1) print $6}' | xargs -I '{}' find '{}' -xdev -nouser -print 2>/dev/null | xargs chown $USER
+        df --local -P | awk '{if (NR!=1) print $6}' | xargs -I '{}' find '{}' -xdev -nouser -print 2>/dev/null | xargs chown "$USER"
     else
         ok "No unowned files found, nothing to apply"
     fi
diff --git a/bin/hardening/6.1.12_find_ungrouped_files.sh b/bin/hardening/6.1.12_find_ungrouped_files.sh
index 64639f3..99bd08e 100755
--- a/bin/hardening/6.1.12_find_ungrouped_files.sh
+++ b/bin/hardening/6.1.12_find_ungrouped_files.sh
@@ -48,7 +48,7 @@ apply() {
     fi
     if [ -n "$RESULT" ]; then
         warn "Applying chgrp on all ungrouped files in the system"
-        df --local -P | awk '{if (NR!=1) print $6}' | xargs -I '{}' find '{}' -xdev -nogroup -print 2>/dev/null | xargs chgrp $GROUP
+        df --local -P | awk '{if (NR!=1) print $6}' | xargs -I '{}' find '{}' -xdev -nogroup -print 2>/dev/null | xargs chgrp "$GROUP"
     else
         ok "No ungrouped files found, nothing to apply"
     fi
diff --git a/bin/hardening/6.2.3_remove_legacy_shadow_entries.sh b/bin/hardening/6.2.3_remove_legacy_shadow_entries.sh
index f430fac..44e78d4 100755
--- a/bin/hardening/6.2.3_remove_legacy_shadow_entries.sh
+++ b/bin/hardening/6.2.3_remove_legacy_shadow_entries.sh
@@ -34,8 +34,8 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    if grep '^+:' $FILE -q; then
-        RESULT=$(grep '^+:' $FILE)
+    if grep '^+:' "$FILE" -q; then
+        RESULT=$(grep '^+:' "$FILE")
         warn "Some accounts have a legacy password entry"
         for LINE in $RESULT; do
             info "Removing $LINE from $FILE"
diff --git a/bin/hardening/99.1_timeout_tty.sh b/bin/hardening/99.1_timeout_tty.sh
index a7a9654..83b1958 100755
--- a/bin/hardening/99.1_timeout_tty.sh
+++ b/bin/hardening/99.1_timeout_tty.sh
@@ -26,7 +26,7 @@ FILE='/etc/profile.d/CIS_99.1_timeout.sh'
 audit() {
     SEARCH_RES=0
     for FILE_SEARCHED in $FILES_TO_SEARCH; do
-        if [ $SEARCH_RES = 1 ]; then break; fi
+        if [ "$SEARCH_RES" = 1 ]; then break; fi
         if test -d "$FILE_SEARCHED"; then
             debug "$FILE_SEARCHED is a directory"
             # shellcheck disable=2044
@@ -59,7 +59,7 @@ audit() {
 apply() {
     SEARCH_RES=0
     for FILE_SEARCHED in $FILES_TO_SEARCH; do
-        if [ $SEARCH_RES = 1 ]; then break; fi
+        if [ "$SEARCH_RES" = 1 ]; then break; fi
         if test -d "$FILE_SEARCHED"; then
             debug "$FILE_SEARCHED is a directory"
             # shellcheck disable=2044
@@ -87,9 +87,9 @@ apply() {
         warn "$PATTERN is not present in $FILES_TO_SEARCH"
         touch "$FILE"
         chmod 644 "$FILE"
-        add_end_of_file $FILE "$PATTERN$VALUE"
-        add_end_of_file $FILE "readonly TMOUT"
-        add_end_of_file $FILE "export TMOUT"
+        add_end_of_file "$FILE" "$PATTERN$VALUE"
+        add_end_of_file "$FILE" "readonly TMOUT"
+        add_end_of_file "$FILE" "export TMOUT"
     else
         ok "$PATTERN is present in $FILES_TO_SEARCH"
     fi
diff --git a/bin/hardening/99.2_disable_usb_devices.sh b/bin/hardening/99.2_disable_usb_devices.sh
index 2acae0c..c0ad231 100755
--- a/bin/hardening/99.2_disable_usb_devices.sh
+++ b/bin/hardening/99.2_disable_usb_devices.sh
@@ -24,8 +24,8 @@ FILE='/etc/udev/rules.d/10-CIS_99.2_usb_devices.sh'
 audit() {
     SEARCH_RES=0
     for FILE_SEARCHED in $FILES_TO_SEARCH; do
-        if [ $SEARCH_RES = 1 ]; then break; fi
-        if $SUDO_CMD test -d $FILE_SEARCHED; then
+        if [ "$SEARCH_RES" = 1 ]; then break; fi
+        if $SUDO_CMD test -d "$FILE_SEARCHED"; then
             debug "$FILE_SEARCHED is a directory"
             for file_in_dir in $($SUDO_CMD ls $FILE_SEARCHED); do
                 does_pattern_exist_in_file "$FILE_SEARCHED/$file_in_dir" "^$PATTERN"
@@ -56,8 +56,8 @@ audit() {
 apply() {
     SEARCH_RES=0
     for FILE_SEARCHED in $FILES_TO_SEARCH; do
-        if [ $SEARCH_RES = 1 ]; then break; fi
-        if test -d $FILE_SEARCHED; then
+        if [ "$SEARCH_RES" = 1 ]; then break; fi
+        if test -d "$FILE_SEARCHED"; then
             debug "$FILE_SEARCHED is a directory"
             for file_in_dir in $(ls $FILE_SEARCHED); do
                 does_pattern_exist_in_file "$FILE_SEARCHED/$file_in_dir" "^$PATTERN"
@@ -83,7 +83,7 @@ apply() {
         warn "$PATTERN is not present in $FILES_TO_SEARCH"
         touch "$FILE"
         chmod 644 "$FILE"
-        add_end_of_file $FILE '
+        add_end_of_file "$FILE" '
 # By default, disable all.
 ACTION=="add", SUBSYSTEMS=="usb", TEST=="authorized_default", ATTR{authorized_default}="0"
 
diff --git a/bin/hardening/99.3.4_acc_logindefs_sha512.sh b/bin/hardening/99.3.4_acc_logindefs_sha512.sh
index d4995ac..e596138 100755
--- a/bin/hardening/99.3.4_acc_logindefs_sha512.sh
+++ b/bin/hardening/99.3.4_acc_logindefs_sha512.sh
@@ -21,10 +21,10 @@ CONF_LINE="ENCRYPT_METHOD SHA512"
 # This function will be called if the script status is on enabled / audit mode
 audit() {
     # Check conf file for default SHA512 hash
-    if $SUDO_CMD [ ! -r $CONF_FILE ]; then
+    if $SUDO_CMD [ ! -r "$CONF_FILE" ]; then
         crit "$CONF_FILE is not readable"
     else
-        does_pattern_exist_in_file $CONF_FILE "^ *${CONF_LINE/ /[[:space:]]+}"
+        does_pattern_exist_in_file "$CONF_FILE" "^ *${CONF_LINE/ /[[:space:]]+}"
         if [ "$FNRET" = 0 ]; then
             ok "$CONF_LINE is present in $CONF_FILE"
         else
@@ -35,14 +35,14 @@ audit() {
 
 # This function will be called if the script status is on enabled mode
 apply() {
-    does_pattern_exist_in_file $CONF_FILE "^ *${CONF_LINE/ /[[:space:]]+}"
+    does_pattern_exist_in_file "$CONF_FILE" "^ *${CONF_LINE/ /[[:space:]]+}"
     if [ "$FNRET" = 0 ]; then
         ok "$CONF_LINE is present in $CONF_FILE"
     else
         warn "$CONF_LINE is not present in $CONF_FILE, adding it"
         does_pattern_exist_in_file "$CONF_FILE" "^$(echo "$CONF_LINE" | cut -d ' ' -f1)"
         if [ "$FNRET" != 0 ]; then
-            add_end_of_file $CONF_FILE "$CONF_LINE"
+            add_end_of_file "$CONF_FILE" "$CONF_LINE"
         else
             info "Parameter $SSH_PARAM is present but with the wrong value -- Fixing"
             replace_in_file "$CONF_FILE" "^$(echo "$CONF_LINE" | cut -d ' ' -f1)[[:space:]]*.*" "$CONF_LINE"
diff --git a/bin/hardening/99.5.1_ssh_auth_pubk_only.sh b/bin/hardening/99.5.1_ssh_auth_pubk_only.sh
index 23afd16..46d7284 100755
--- a/bin/hardening/99.5.1_ssh_auth_pubk_only.sh
+++ b/bin/hardening/99.5.1_ssh_auth_pubk_only.sh
@@ -32,7 +32,7 @@ audit() {
             SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
             SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
             PATTERN="^${SSH_PARAM}[[:space:]]+$SSH_VALUE"
-            does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+            does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
             if [ "$FNRET" = 0 ]; then
                 ok "$PATTERN is present in $FILE"
             else
@@ -60,9 +60,9 @@ apply() {
             ok "$PATTERN is present in $FILE"
         else
             warn "$PATTERN is not present in $FILE, adding it"
-            does_pattern_exist_in_file_nocase $FILE "^${SSH_PARAM}"
+            does_pattern_exist_in_file_nocase "$FILE" "^${SSH_PARAM}"
             if [ "$FNRET" != 0 ]; then
-                add_end_of_file $FILE "$SSH_PARAM $SSH_VALUE"
+                add_end_of_file "$FILE" "$SSH_PARAM $SSH_VALUE"
             else
                 info "Parameter $SSH_PARAM is present but with the wrong value -- Fixing"
                 replace_in_file $FILE "^${SSH_PARAM}[[:space:]]+.*" "$SSH_PARAM $SSH_VALUE"
diff --git a/bin/hardening/99.5.2.3_ssh_cry_rekey.sh b/bin/hardening/99.5.2.3_ssh_cry_rekey.sh
index 63d52bb..ae60936 100755
--- a/bin/hardening/99.5.2.3_ssh_cry_rekey.sh
+++ b/bin/hardening/99.5.2.3_ssh_cry_rekey.sh
@@ -44,10 +44,10 @@ audit() {
     else
         ok "$PACKAGE is installed"
         for SSH_OPTION in $OPTIONS; do
-            SSH_PARAM=$(echo $SSH_OPTION | cut -d= -f 1)
-            SSH_VALUE=$(echo $SSH_OPTION | cut -d= -f 2)
+            SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
+            SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
             PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-            does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+            does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
             if [ "$FNRET" = 0 ]; then
                 ok "$PATTERN is present in $FILE"
             else
@@ -67,22 +67,22 @@ apply() {
         apt_install "$PACKAGE"
     fi
     for SSH_OPTION in $OPTIONS; do
-        SSH_PARAM=$(echo $SSH_OPTION | cut -d= -f 1)
-        SSH_VALUE=$(echo $SSH_OPTION | cut -d= -f 2)
+        SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
+        SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+        does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
             warn "$PATTERN is not present in $FILE, adding it"
-            does_pattern_exist_in_file_nocase $FILE "^${SSH_PARAM}"
+            does_pattern_exist_in_file_nocase "$FILE" "^${SSH_PARAM}"
             if [ "$FNRET" != 0 ]; then
                 # shellcheck disable=SC2001
                 SSH_VALUE=$(sed 's/\\s+/ /' <<<"$SSH_VALUE")
-                add_end_of_file $FILE "$SSH_PARAM $SSH_VALUE"
+                add_end_of_file "$FILE" "$SSH_PARAM $SSH_VALUE"
             else
                 info "Parameter $SSH_PARAM is present but with the wrong value -- Fixing"
-                replace_in_file $FILE "^${SSH_PARAM}[[:space:]]*.*" "$SSH_PARAM $SSH_VALUE"
+                replace_in_file "$FILE" "^${SSH_PARAM}[[:space:]]*.*" "$SSH_PARAM $SSH_VALUE"
             fi
             /etc/init.d/ssh reload >/dev/null 2>&1
         fi
diff --git a/bin/hardening/99.5.3_ssh_disable_features.sh b/bin/hardening/99.5.3_ssh_disable_features.sh
index 9988acc..df31af8 100755
--- a/bin/hardening/99.5.3_ssh_disable_features.sh
+++ b/bin/hardening/99.5.3_ssh_disable_features.sh
@@ -31,7 +31,7 @@ audit() {
             SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
             SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
             PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-            does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+            does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
             if [ "$FNRET" = 0 ]; then
                 ok "$PATTERN is present in $FILE"
             else
@@ -54,17 +54,17 @@ apply() {
         SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
         SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+        does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
             warn "$PATTERN is not present in $FILE, adding it"
-            does_pattern_exist_in_file_nocase $FILE "^${SSH_PARAM}"
+            does_pattern_exist_in_file_nocase "$FILE" "^${SSH_PARAM}"
             if [ "$FNRET" != 0 ]; then
-                add_end_of_file $FILE "$SSH_PARAM $SSH_VALUE"
+                add_end_of_file "$FILE" "$SSH_PARAM $SSH_VALUE"
             else
                 info "Parameter $SSH_PARAM is present but with the wrong value -- Fixing"
-                replace_in_file $FILE "^${SSH_PARAM}[[:space:]]*.*" "$SSH_PARAM $SSH_VALUE"
+                replace_in_file "$FILE" "^${SSH_PARAM}[[:space:]]*.*" "$SSH_PARAM $SSH_VALUE"
             fi
             /etc/init.d/ssh reload >/dev/null 2>&1
         fi
diff --git a/bin/hardening/99.5.4_ssh_keys_from.sh b/bin/hardening/99.5.4_ssh_keys_from.sh
index 31d68f2..b27d340 100755
--- a/bin/hardening/99.5.4_ssh_keys_from.sh
+++ b/bin/hardening/99.5.4_ssh_keys_from.sh
@@ -55,13 +55,13 @@ check_ip() {
         ok_ips=$(sed 's/ $//' <<<"${ok_ips_allowed}")
         # shellcheck disable=SC2001
         bad_ips=$(sed 's/ $//' <<<"${bad_ips}")
-        if [[ -z $bad_ips ]]; then
-            if [[ -n $ok_ips ]]; then
+        if [[ -z "$bad_ips" ]]; then
+            if [[ -n "$ok_ips" ]]; then
                 ok "Line $linum of $file allows ssh access only from allowed IPs ($ok_ips)."
             fi
         else
             crit "Line $linum of $file allows ssh access from (${bad_ips}) that are not allowed."
-            if [[ -n $ok_ips ]]; then
+            if [[ -n "$ok_ips" ]]; then
                 ok "Line $linum of $file allows ssh access from at least allowed IPs ($ok_ips)."
             fi
         fi
@@ -143,7 +143,7 @@ audit() {
                 continue
             fi
             check_dir /home/"${user}"
-            if [ $FOUND_AUTHKF = 0 ]; then
+            if [ "$FOUND_AUTHKF" = 0 ]; then
                 warn "$user has a valid shell but no authorized_keys file"
             fi
         fi
diff --git a/bin/hardening/99.5.5_ssh_strict_modes.sh b/bin/hardening/99.5.5_ssh_strict_modes.sh
index 341279a..9488b04 100755
--- a/bin/hardening/99.5.5_ssh_strict_modes.sh
+++ b/bin/hardening/99.5.5_ssh_strict_modes.sh
@@ -27,10 +27,10 @@ audit() {
     else
         ok "$PACKAGE is installed"
         for SSH_OPTION in $OPTIONS; do
-            SSH_PARAM=$(echo $SSH_OPTION | cut -d= -f 1)
-            SSH_VALUE=$(echo $SSH_OPTION | cut -d= -f 2)
+            SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
+            SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
             PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-            does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+            does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
             if [ "$FNRET" = 0 ]; then
                 ok "$PATTERN is present in $FILE"
             else
@@ -50,20 +50,20 @@ apply() {
         apt_install "$PACKAGE"
     fi
     for SSH_OPTION in $OPTIONS; do
-        SSH_PARAM=$(echo $SSH_OPTION | cut -d= -f 1)
-        SSH_VALUE=$(echo $SSH_OPTION | cut -d= -f 2)
+        SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
+        SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+        does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
             warn "$PATTERN is not present in $FILE, adding it"
             does_pattern_exist_in_file_nocase $FILE "^${SSH_PARAM}"
             if [ "$FNRET" != 0 ]; then
-                add_end_of_file $FILE "$SSH_PARAM $SSH_VALUE"
+                add_end_of_file "$FILE" "$SSH_PARAM $SSH_VALUE"
             else
                 info "Parameter $SSH_PARAM is present but with the wrong value -- Fixing"
-                replace_in_file $FILE "^${SSH_PARAM}[[:space:]]*.*" "$SSH_PARAM $SSH_VALUE"
+                replace_in_file "$FILE" "^${SSH_PARAM}[[:space:]]*.*" "$SSH_PARAM $SSH_VALUE"
             fi
             /etc/init.d/ssh reload >/dev/null 2>&1
         fi
diff --git a/bin/hardening/99.5.6_ssh_sys_accept_env.sh b/bin/hardening/99.5.6_ssh_sys_accept_env.sh
index d3ae5d7..635ad0d 100755
--- a/bin/hardening/99.5.6_ssh_sys_accept_env.sh
+++ b/bin/hardening/99.5.6_ssh_sys_accept_env.sh
@@ -28,7 +28,7 @@ audit() {
         crit "$PACKAGE is not installed!"
     else
         ok "$PACKAGE is installed"
-        does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+        does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
@@ -46,19 +46,19 @@ apply() {
         crit "$PACKAGE is absent, installing it"
         apt_install "$PACKAGE"
     fi
-    does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+    does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
     if [ "$FNRET" = 0 ]; then
         ok "$PATTERN is present in $FILE"
     else
         warn "$PATTERN is not present in $FILE, adding it"
-        does_pattern_exist_in_file_nocase $FILE "^$PATTERN"
+        does_pattern_exist_in_file_nocase "$FILE" "^$PATTERN"
         # shellcheck disable=SC2001
         PATTERN=$(sed 's/\^//' <<<"$PATTERN" | sed -r 's/\\s\*//' | sed -r 's/\\s\+/ /g' | sed 's/\\//g')
         if [ "$FNRET" != 0 ]; then
-            add_end_of_file $FILE "$PATTERN"
+            add_end_of_file "$FILE" "$PATTERN"
         else
             info "Parameter $SSH_PARAM is present but with the wrong value -- Fixing"
-            replace_in_file $FILE "^${SSH_PARAM}[[:space:]]*.*" "$PATTERN"
+            replace_in_file "$FILE" "^${SSH_PARAM}[[:space:]]*.*" "$PATTERN"
         fi
         /etc/init.d/ssh reload >/dev/null 2>&1
     fi
diff --git a/bin/hardening/99.5.8_ssh_sys_sandbox.sh b/bin/hardening/99.5.8_ssh_sys_sandbox.sh
index 99f5ee2..2fb0a82 100755
--- a/bin/hardening/99.5.8_ssh_sys_sandbox.sh
+++ b/bin/hardening/99.5.8_ssh_sys_sandbox.sh
@@ -29,10 +29,10 @@ audit() {
     else
         ok "$PACKAGE is installed"
         for SSH_OPTION in $OPTIONS; do
-            SSH_PARAM=$(echo $SSH_OPTION | cut -d= -f 1)
-            SSH_VALUE=$(echo $SSH_OPTION | cut -d= -f 2)
+            SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
+            SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
             PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-            does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+            does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
             if [ "$FNRET" = 0 ]; then
                 ok "$PATTERN is present in $FILE"
             else
@@ -52,20 +52,20 @@ apply() {
         apt_install "$PACKAGE"
     fi
     for SSH_OPTION in $OPTIONS; do
-        SSH_PARAM=$(echo $SSH_OPTION | cut -d= -f 1)
-        SSH_VALUE=$(echo $SSH_OPTION | cut -d= -f 2)
+        SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
+        SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+        does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
             warn "$PATTERN is not present in $FILE, adding it"
-            does_pattern_exist_in_file_nocase $FILE "^${SSH_PARAM}"
+            does_pattern_exist_in_file_nocase "$FILE" "^${SSH_PARAM}"
             if [ "$FNRET" != 0 ]; then
-                add_end_of_file $FILE "$SSH_PARAM $SSH_VALUE"
+                add_end_of_file "$FILE" "$SSH_PARAM $SSH_VALUE"
             else
                 info "Parameter $SSH_PARAM is present but with the wrong value -- Fixing"
-                replace_in_file $FILE "^${SSH_PARAM}[[:space:]]*.*" "$SSH_PARAM $SSH_VALUE"
+                replace_in_file "$FILE" "^${SSH_PARAM}[[:space:]]*.*" "$SSH_PARAM $SSH_VALUE"
             fi
             /etc/init.d/ssh reload >/dev/null 2>&1
         fi
diff --git a/bin/hardening/99.5.9_ssh_loglevel.sh b/bin/hardening/99.5.9_ssh_loglevel.sh
index 99d0f3f..0d81e49 100755
--- a/bin/hardening/99.5.9_ssh_loglevel.sh
+++ b/bin/hardening/99.5.9_ssh_loglevel.sh
@@ -29,10 +29,10 @@ audit() {
     else
         ok "$PACKAGE is installed"
         for SSH_OPTION in $OPTIONS; do
-            SSH_PARAM=$(echo $SSH_OPTION | cut -d= -f 1)
-            SSH_VALUE=$(echo $SSH_OPTION | cut -d= -f 2)
+            SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
+            SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
             PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-            does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+            does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
             if [ "$FNRET" = 0 ]; then
                 ok "$PATTERN is present in $FILE"
             else
@@ -52,20 +52,20 @@ apply() {
         apt_install "$PACKAGE"
     fi
     for SSH_OPTION in $OPTIONS; do
-        SSH_PARAM=$(echo $SSH_OPTION | cut -d= -f 1)
-        SSH_VALUE=$(echo $SSH_OPTION | cut -d= -f 2)
+        SSH_PARAM=$(echo "$SSH_OPTION" | cut -d= -f 1)
+        SSH_VALUE=$(echo "$SSH_OPTION" | cut -d= -f 2)
         PATTERN="^${SSH_PARAM}[[:space:]]*$SSH_VALUE"
-        does_pattern_exist_in_file_nocase $FILE "$PATTERN"
+        does_pattern_exist_in_file_nocase "$FILE" "$PATTERN"
         if [ "$FNRET" = 0 ]; then
             ok "$PATTERN is present in $FILE"
         else
             warn "$PATTERN is not present in $FILE, adding it"
-            does_pattern_exist_in_file_nocase $FILE "^${SSH_PARAM}"
+            does_pattern_exist_in_file_nocase "$FILE" "^${SSH_PARAM}"
             if [ "$FNRET" != 0 ]; then
-                add_end_of_file $FILE "$SSH_PARAM $SSH_VALUE"
+                add_end_of_file "$FILE" "$SSH_PARAM $SSH_VALUE"
             else
                 info "Parameter $SSH_PARAM is present but with the wrong value -- Fixing"
-                replace_in_file $FILE "^${SSH_PARAM}[[:space:]]*.*" "$SSH_PARAM $SSH_VALUE"
+                replace_in_file "$FILE" "^${SSH_PARAM}[[:space:]]*.*" "$SSH_PARAM $SSH_VALUE"
             fi
             /etc/init.d/ssh reload >/dev/null 2>&1
         fi
diff --git a/lib/common.sh b/lib/common.sh
index a5e34f4..f351873 100644
--- a/lib/common.sh
+++ b/lib/common.sh
@@ -70,7 +70,7 @@ crit() {
     if [ "${BATCH_MODE:-0}" -eq 1 ]; then
         BATCH_OUTPUT="$BATCH_OUTPUT KO{$*}"
     else
-        if [ $MACHINE_LOG_LEVEL -ge 1 ]; then _logger "$BRED" "[ KO ] $*"; fi
+        if [ "$MACHINE_LOG_LEVEL" -ge 1 ]; then _logger "$BRED" "[ KO ] $*"; fi
     fi
     # This variable incrementation is used to measure failure or success in tests
     CRITICAL_ERRORS_NUMBER=$((CRITICAL_ERRORS_NUMBER + 1))
@@ -80,7 +80,7 @@ warn() {
     if [ "${BATCH_MODE:-0}" -eq 1 ]; then
         BATCH_OUTPUT="$BATCH_OUTPUT WARN{$*}"
     else
-        if [ $MACHINE_LOG_LEVEL -ge 2 ]; then _logger "$BYELLOW" "[WARN] $*"; fi
+        if [ "$MACHINE_LOG_LEVEL" -ge 2 ]; then _logger "$BYELLOW" "[WARN] $*"; fi
     fi
 }
 
@@ -88,7 +88,7 @@ ok() {
     if [ "${BATCH_MODE:-0}" -eq 1 ]; then
         BATCH_OUTPUT="$BATCH_OUTPUT OK{$*}"
     else
-        if [ $MACHINE_LOG_LEVEL -ge 3 ]; then _logger "$BGREEN" "[ OK ] $*"; fi
+        if [ "$MACHINE_LOG_LEVEL" -ge 3 ]; then _logger "$BGREEN" "[ OK ] $*"; fi
     fi
 }
 
diff --git a/lib/main.sh b/lib/main.sh
index 6a81b6b..e43f140 100644
--- a/lib/main.sh
+++ b/lib/main.sh
@@ -128,7 +128,7 @@ disabled | false)
 esac
 
 if [ "$CRITICAL_ERRORS_NUMBER" -eq 0 ]; then
-    if [ $BATCH_MODE -eq 1 ]; then
+    if [ "$BATCH_MODE" -eq 1 ]; then
         BATCH_OUTPUT="OK $SCRIPT_NAME $BATCH_OUTPUT"
         becho "$BATCH_OUTPUT"
     else
diff --git a/lib/utils.sh b/lib/utils.sh
index bf60961..b1ca276 100644
--- a/lib/utils.sh
+++ b/lib/utils.sh
@@ -13,7 +13,7 @@ has_sysctl_param_expected_result() {
 
     if [ "$($SUDO_CMD sysctl "$SYSCTL_PARAM" 2>/dev/null)" = "$SYSCTL_PARAM = $EXP_RESULT" ]; then
         FNRET=0
-    elif [ $? = 255 ]; then
+    elif [ "$?" = 255 ]; then
         debug "$SYSCTL_PARAM does not exist"
         FNRET=255
     else
@@ -147,7 +147,7 @@ does_pattern_exist_in_file_multiline() {
 
     debug "Checking if multiline pattern: $PATTERN is present in $FILE"
     if $SUDO_CMD [ -r "$FILE" ]; then
-        debug "$SUDO_CMD grep -v '^[[:space:]]*#' $FILE | tr '\n' ' ' | grep -Pq -- "$PATTERN""
+        debug "$SUDO_CMD grep -v '^[[:space:]]*#' $FILE | tr '\n' ' ' | grep -Pq -- $PATTERN"
         if $SUDO_CMD grep -v '^[[:space:]]*#' "$FILE" | tr '\n' ' ' | grep -Pq -- "$PATTERN"; then
             debug "Pattern found in $FILE"
             FNRET=0
@@ -239,7 +239,7 @@ does_group_exist() {
 
 is_service_enabled() {
     local SERVICE=$1
-    if [ $($SUDO_CMD find /etc/rc?.d/ -name "S*$SERVICE" -print | wc -l) -gt 0 ]; then
+    if [ "$($SUDO_CMD find /etc/rc?.d/ -name "S*$SERVICE" -print | wc -l)" -gt 0 ]; then
         debug "Service $SERVICE is enabled"
         FNRET=0
     else
@@ -385,7 +385,7 @@ apt_update_if_needed() {
     if [ -e /var/cache/apt/pkgcache.bin ]; then
         UPDATE_AGE=$(($(date +%s) - $(stat -c '%Y' /var/cache/apt/pkgcache.bin)))
 
-        if [ $UPDATE_AGE -gt 21600 ]; then
+        if [ "$UPDATE_AGE" -gt 21600 ]; then
             # update too old, refresh database
             $SUDO_CMD apt-get update -y >/dev/null 2>/dev/null
         fi
@@ -438,7 +438,7 @@ is_pkg_installed() {
 get_debian_major_version() {
     DEB_MAJ_VER=""
     does_file_exist /etc/debian_version
-    if [ $FNRET ]; then
+    if [ "$FNRET" = 0 ]; then
         DEB_MAJ_VER=$(cut -d '.' -f1 /etc/debian_version)
     else
         # shellcheck disable=2034
diff --git a/shellcheck/launch_shellcheck.sh b/shellcheck/launch_shellcheck.sh
index c75aa02..c54d455 100755
--- a/shellcheck/launch_shellcheck.sh
+++ b/shellcheck/launch_shellcheck.sh
@@ -5,7 +5,7 @@
 files=""
 retval=0
 
-if [ $# -eq 0 ]; then
+if [ "$#" -eq 0 ]; then
     files=$(find . -name "*.sh" | sort -V)
 else
     files="$*"