diff --git a/install.sh b/install.sh
index 2ccc82e..ce4101e 100755
--- a/install.sh
+++ b/install.sh
@@ -8,7 +8,7 @@ if [ "$(whoami)" != "root" ]; then
 fi
 
 for dep in getent grep useradd groupadd gpasswd cut ps chmod chown; do
-    if $(which $dep) &>/dev/null; then
+    if which $dep &>/dev/null; then
         true
     else
         echo "$dep utility missing. Please install before running this script. Exiting..."
@@ -19,7 +19,7 @@ done
 DESTDIR="/usr/bin/"
 echo "Destination directory for hostsblock is $DESTDIR. Enter a new path or press Enter to keep as is."
 read -p "$DESTDIR " d
-if [ "$d" != "" ] || [ -n $d ]; then
+if [ "$d" != "" ] || [[ -n $d ]]; then
     DESTDIR="$d"
 fi
 
@@ -29,7 +29,7 @@ else
     HOMEDIR="/var/lib/hostsblock"
     echo "Creating user and group 'hostsblock' with home directory $HOMEDIR. Enter a new path or press Enter to keep as is."
     read -p "$HOMEDIR " h
-    if [ "$h" != "" ] || [ -n $h ]; then
+    if [ "$h" != "" ] || [[ -n $h ]]; then
         HOMEDIR="$h"
     fi
     echo "Creating user and group 'hostsblock' with home directory $HOMEDIR..."
@@ -46,8 +46,8 @@ fi
 gpasswd -a hostsblock hostsblock
 gpasswd -A hostsblock hostsblock
 
-if ps aux | grep [d]nsmasq | tr -s ' ' | cut -d' ' -f 11- | grep -q [d]nsmasq; then
-    dnsmasq_user=$(ps aux | grep [d]nsmasq | tr -s ' ' | cut -d' ' -f 1)
+if ps aux | grep '[d]nsmasq' | tr -s ' ' | cut -d' ' -f 11- | grep -q '[d]nsmasq'; then
+    dnsmasq_user=$(ps aux | grep '[d]nsmasq' | tr -s ' ' | cut -d' ' -f 1)
     echo -e "You appear to be running dnsmasq under user $dnsmasq_user. If you will be using hostsblock\nwith dnsmasq as a caching daemon, dnsmasq needs read access to hostsblock's home directory.\nTo do so, should I add $dnsmasq_user to the hostblock group?"
     read -p "y/N " e
     if [ "$e" == "y" ] || [ "$e" == "Y" ]; then
@@ -57,7 +57,7 @@ if ps aux | grep [d]nsmasq | tr -s ' ' | cut -d' ' -f 11- | grep -q [d]nsmasq; t
 else
     echo -e "If you are using hostsblock with a dns cacher, you should add the user under which the cacher\nruns to the 'hostsblock' group so that the daemon can access your generated host file.\nEnter the user of the DNS daemon or leave blank to add no additional user."
     read -p "[No DNS user] " dns
-    if [ "$dns" != "" ] || [ -n $dns ]; then
+    if [ "$dns" != "" ] || [[ -n $dns ]]; then
         gpasswd -a "$dns" hostsblock
         gpasswd -M "$dns" hostsblock
     fi
diff --git a/src/hostsblock.sh b/src/hostsblock.sh
index 23bf183..5301f09 100755
--- a/src/hostsblock.sh
+++ b/src/hostsblock.sh
@@ -3,7 +3,7 @@
 # SUBROUTINES
 
 _notify() {
-    [ $_verbosity -ge $1 ] && echo "$2"
+    [ "$_verbosity" -ge "$1" ] && echo "$2"
 }
 
 _count_hosts() {
@@ -16,15 +16,15 @@ _count_hosts() {
 _strip_entries() {
     which pigz &>/dev/null
     if [ $? -eq 0 ]; then
-        pigz -dc "$2" | grep -v "$1" | pigz $pigz_opt -c - > "$2".tmp
+        pigz -dc "$2" | grep -v "$1" | pigz "$pigz_opt" -c - > "$2".tmp
     else
-        gzip -dc "$2" | grep -v "$1" | gzip $gzip_opt -c - > "$2".tmp
+        gzip -dc "$2" | grep -v "$1" | gzip "$gzip_opt" -c - > "$2".tmp
     fi
 }
 
 _extract_entries() {
     if [ ! -d "$_cachefile_dir" ]; then
-        mkdir $_v -p -- "$_cachefile_dir"
+        mkdir "$_v" -p -- "$_cachefile_dir"
         if [ $? -ne 0 ]; then
             _notify 0 "FAILED TO CREATE DIRECTORY $_cachefile_dir. EXITING..."
             exit 9
@@ -34,19 +34,19 @@ _extract_entries() {
     case "$_decompresser" in
         none)
             _compress_exit=0
-            cp $_v -- "$_cachefile" "$_cachefile_dir"/ || _notify 1 "FAILED to move ${_cachefile##*/} to $_cachefile_dir."
+            cp "$_v" -- "$_cachefile" "$_cachefile_dir"/ || _notify 1 "FAILED to move ${_cachefile##*/} to $_cachefile_dir."
         ;;
         unzip)
-            unzip -B -o -j $_v_unzip -- "$_cachefile"
+            unzip -B -o -j "$_v_unzip" -- "$_cachefile"
             _compress_exit=$?
             [ $_compress_exit -ne 0 ] && _notify 1 "FAILED to unzip ${_cachefile##*/}."
         ;;
         7z*)
-            if [ $_verbosity -le 1 ]; then
-                eval $_7zip_available e "$_cachefile" &>/dev/null
+            if [ "$_verbosity" -le 1 ]; then
+                eval "$_7zip_available" e "$_cachefile" &>/dev/null
                 _compress_exit=$?
             else
-                eval $_7zip_available e "$_cachefile"
+                eval "$_7zip_available" e "$_cachefile"
                 _compress_exit=$?
             fi
             [ $_compress_exit -ne 0 ] && _notify 1 "FAILED to un7zip ${_cachefile##*/}."
@@ -59,7 +59,7 @@ _extract_entries() {
           sed -e "s/\#.*//g" -e "s/[[:space:]]$//g" -e "s/$_notredirect/$redirecturl/g" | sort -u | grep -Fvf "$whitelist" | \
           sed "s|$| \! $_cachefile_url|g" > "$_target_hostsfile"
         if [ $? -eq 0 ]; then
-            [ $_verbosity -ge 2 ] && _count_hosts "$_target_hostsfile"
+            [ "$_verbosity" -ge 2 ] && _count_hosts "$_target_hostsfile"
         else
             _notify 1 "FAILED to extract any obvious entries from ${_cachefile##*/}."
         fi
@@ -68,11 +68,11 @@ _extract_entries() {
           sed -e "s/\#.*//g" -e "s/[[:space:]]$//g" | sort -u | grep -Fvf "$whitelist" | sed "s|$| \! $_cachefile_url|g" \
           >> "$_target_hostsfile"
         if [ $? -eq 0 ]; then
-            [ $_verbosity -ge 2 ] && _count_hosts "$_target_hostsfile"
+            [ "$_verbosity" -ge 2 ] && _count_hosts "$_target_hostsfile"
         else
             _notify 1 "FAILED to extract any less-obvious entries from ${_cachefile##*/}."
         fi
-        cd "$tmpdir"/hostsblock && rm $_v -r -- "$_cachefile_dir" || _notify 1 "FAILED to delete $_cachefile_dir."
+        cd "$tmpdir"/hostsblock && rm "$_v" -r -- "$_cachefile_dir" || _notify 1 "FAILED to delete $_cachefile_dir."
     fi
 }
 
@@ -89,9 +89,9 @@ _check_url() {
       tr '\n' ',' | sed "s/,$//g")
     _block_matches_count=$(echo "$_block_matches" | wc -w)
     _redirect_matches_count=$(echo "$_redirect_matches" | wc -w)
-    if [ $_block_matches_count -gt 0 ] || [ $_redirect_matches_count -gt 0 ]; then
-        [ $_block_matches_count -gt 0 ] && echo -e "\n'$@' \e[1;31mBLOCKED \e[0mby blocklist(s)${_block_matches}"
-        [ $_redirect_matches_count -gt 0 ] && echo -e "\n'$@' \e[1;33mREDIRECTED \e[0m$_redirect_matches"
+    if [ "$_block_matches_count" -gt 0 ] || [ "$_redirect_matches_count" -gt 0 ]; then
+        [ "$_block_matches_count" -gt 0 ] && echo -e "\n'$@' \e[1;31mBLOCKED \e[0mby blocklist(s)${_block_matches}"
+        [ "$_redirect_matches_count" -gt 0 ] && echo -e "\n'$@' \e[1;33mREDIRECTED \e[0m$_redirect_matches"
         echo -e "\t1) Unblock/unredirect just $@\n\t2) Unblock/unredirect all sites containing url $@\n\t3) Keep blocked/redirected"
         read -p "1-3 (default: 3): " b
         if [[ $b == 1 || "$b" == "1" ]]; then
@@ -100,7 +100,7 @@ _check_url() {
             _strip_entries " $@ \!" "$annotate"
             sed -i "/ $@$/d" "$blacklist"
             sed -i "/ $@$/d" "$hostsfile"
-            [ ! -d "$tmpdir"/hostsblock ] && mkdir $_v -p "$tmpdir"/hostsblock
+            [ ! -d "$tmpdir"/hostsblock ] && mkdir "$_v" -p "$tmpdir"/hostsblock
             touch "$tmpdir"/hostsblock/changed
         elif [[ $b == 2 || "$b" == "2" ]]; then
             echo "Unblocking all sites containing url $@"
@@ -108,7 +108,7 @@ _check_url() {
             _strip_entries "$@" "$annotate"
             sed -i "/$@/d" "$blacklist"
             sed -i "/$@/d" "$hostsfile"
-            [ ! -d "$tmpdir"/hostsblock ] && mkdir $_v -p "$tmpdir"/hostsblock
+            [ ! -d "$tmpdir"/hostsblock ] && mkdir "$_v" -p "$tmpdir"/hostsblock
             touch "$tmpdir"/hostsblock/changed
         fi
     else
@@ -121,17 +121,17 @@ _check_url() {
               if which pigz &>/dev/null; then
                   pigz -dc "$annotate" > "$tmpdir"/hostsblock/"${annotate##*/}".tmp
                   echo "$redirecturl $@ \! $blacklist" >> "$tmpdir"/hostsblock/"${annotate##*/}".tmp
-                  sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | pigz $pigz_opt -c - > "$annotate"
+                  sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | pigz "$pigz_opt" -c - > "$annotate"
               else
                   gzip -dc "$annotate" > "$tmpdir"/hostsblock/"${annotate##*/}".tmp
                   echo "$redirecturl $@ \! $blacklist" >> "$tmpdir"/hostsblock/"${annotate##*/}".tmp
-                  sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | gzip $gzip_opt -c - > "$annotate"
+                  sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | gzip "$gzip_opt" -c - > "$annotate"
               fi
               rm -f "$_v" -- "$tmpdir"/hostsblock/"${annotate##*/}".tmp
             ) &
             sed -i "/^$@$/d" "$whitelist" &
             echo "$redirecturl $@" >> "$hostsfile" &
-            [ ! -d "$tmpdir"/hostsblock ] && mkdir $_v -p "$tmpdir"/hostsblock
+            [ ! -d "$tmpdir"/hostsblock ] && mkdir "$_v" -p "$tmpdir"/hostsblock
             touch "$tmpdir"/hostsblock/changed
             wait
         elif [[ $c == 2 || "$c" == "2" ]]; then
@@ -141,17 +141,17 @@ _check_url() {
               if which pigz &>/dev/null; then
                   pigz -dc "$annotate" > "$tmpdir"/hostsblock/"${annotate##*/}".tmp
                   echo "$redirecturl $@ \! $blacklist" >> "$tmpdir"/hostsblock/"${annotate##*/}".tmp
-                  sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | pigz $pigz_opt -c - > "$annotate"
+                  sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | pigz "$pigz_opt" -c - > "$annotate"
               else
                   gzip -dc "$annotate" > "$tmpdir"/hostsblock/"${annotate##*/}".tmp
                   echo "$redirecturl $@ \! $blacklist" >> "$tmpdir"/hostsblock/"${annotate##*/}".tmp
-                  sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | gzip $gzip_opt -c - > "$annotate"
+                  sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | gzip "$gzip_opt" -c - > "$annotate"
               fi
               rm -f "$_v" -- "$tmpdir"/hostsblock/"${annotate##*/}".tmp
             ) &
             sed -i "/$@/d" "$whitelist" &
             echo "$redirecturl $@" >> "$hostsfile" &
-            [ ! -d "$tmpdir"/hostsblock ] && mkdir $_v -p "$tmpdir"/hostsblock
+            [ ! -d "$tmpdir"/hostsblock ] && mkdir "$_v" -p "$tmpdir"/hostsblock
             touch "$tmpdir"/hostsblock/changed
         fi
     fi
@@ -189,7 +189,7 @@ while getopts "qvf:huc:" _option; do
         v)  _verbosity=2;;
         q)  _verbosity=0;;
         u)
-            [ ! -d "$tmpdir"/hostsblock ] && mkdir $_v -p "$tmpdir"/hostsblock
+            [ ! -d "$tmpdir"/hostsblock ] && mkdir "$_v" -p "$tmpdir"/hostsblock
             touch "$tmpdir"/hostsblock/changed
         ;;
         c)
@@ -219,13 +219,13 @@ EOF
 done
 
 # SOURCE CONFIG FILE
-if [ $_configfile ]; then
+if [ "$_configfile" ]; then
     if [ -f "$_configfile" ]; then
     . "$_configfile"
-    elif [ $(whoami) != "root" ] && [ -f ${HOME}/.config/hostsblock/hostsblock.conf ]; then
+    elif [ "$(whoami)" != "root" ] && [ -f ${HOME}/.config/hostsblock/hostsblock.conf ]; then
         _notify 1 "Config file $_configfile missing. Using ${HOME}/.config/hostsblock/hostsblock.conf"
         . ${HOME}/.config/hostsblock/hostsblock.conf
-    elif [ $(whoami) != "root" ] && [ -f ${HOME}/hostsblock.conf ]; then
+    elif [ "$(whoami)" != "root" ] && [ -f ${HOME}/hostsblock.conf ]; then
         _notify 1 "Config file $_configfile missing. Using ${HOME}/hostsblock.conf"
         . ${HOME}/hostsblock.conf
     elif [ -f /etc/hostsblock/hostsblock.conf ]; then
@@ -234,9 +234,9 @@ if [ $_configfile ]; then
     else
         _notify 1 "No config files found. Using defaults."
     fi
-elif [ $(whoami) != "root" ] && [ -f ${HOME}/.config/hostsblock/hostsblock.conf ]; then
+elif [ "$(whoami)" != "root" ] && [ -f ${HOME}/.config/hostsblock/hostsblock.conf ]; then
     . ${HOME}/.config/hostsblock/hostsblock.conf
-elif [ $(whoami) != "root" ] && [ -f ${HOME}/hostsblock.conf ]; then
+elif [ "$(whoami)" != "root" ] && [ -f ${HOME}/hostsblock.conf ]; then
     . ${HOME}/hostsblock.conf
 elif [ -f /etc/hostsblock/hostsblock.conf ]; then
     . /etc/hostsblock/hostsblock.conf
@@ -261,7 +261,7 @@ else
 fi
 
 # CHECK FOR CORRECT PRIVILEDGES AND DEPENDENCIES
-if [ $(whoami) != "hostsblock" ]; then
+if [ "$(whoami)" != "hostsblock" ]; then
     echo -e "WRONG PERMISSIONS. RUN AS USER hostsblock, EITHER DIRECTLY OR VIA SUDO, E.G. sudo -u hostsblock $0 $@\n\nYou may have to add the following line to the end of sudoers after typing 'sudo visudo':\n $(whoami)	ALL	=	(hostblock)	NOPASSWD:	$0\n\nExiting..."
     exit 3
 fi
@@ -282,7 +282,7 @@ if [ $_check -eq 1 ] || [ "${0##*/}" == "hostsblock-urlcheck" ]; then
     echo "Checking to see if url is blocked or not..."
     # If run from symlink "hostsblock-urlcheck" _URL will not be set by getopts
     [ "$_URL" == "" ] && _URL="$1"
-    _check_url $(echo "$_URL" | sed -e "s/.*https*:\/\///g" -e "s/[\/?'\" :<>\(\)].*//g")
+    _check_url "$(echo "$_URL" | sed -e "s/.*https*:\/\///g" -e "s/[\/?'\" :<>\(\)].*//g")"
     if [ -f "$tmpdir"/hostsblock/changed ]; then
         if [ $_verbosity -ge 1 ]; then
             postprocess
@@ -345,13 +345,13 @@ else
     # DOWNLOAD BLOCKLISTS
     _notify 1 "Checking blocklists for updates..."
     for _url in ${blocklists[*]}; do
-        _outfile=$(echo $_url | sed -e "s|http:\/\/||g" -e "s|https:\/\/||g" | tr '/%&+?=' '.')
+        _outfile=$(echo "$_url" | sed -e "s|http:\/\/||g" -e "s|https:\/\/||g" | tr '/%&+?=' '.')
         [ -f "$cachedir"/"$_outfile".url ] || echo "$_url" > "$cachedir"/"$_outfile".url
         [ -f "$cachedir"/"$_outfile" ] && _old_sha1sum=$(sha1sum < "$cachedir"/"$_outfile")
 
         # Make process wait until the number of curl processes are less than $max_simultaneous_downloads
-        until [ $(pidof curl | wc -w) -lt $max_simultaneous_downloads ]; do
-            sleep $(pidof sleep | wc -w)
+        until [ "$(pidof curl | wc -w)" -lt $max_simultaneous_downloads ]; do
+            sleep "$(pidof sleep | wc -w)"
         done
 
         # Add a User-Agent and referer string when needed
@@ -491,9 +491,9 @@ else
         (
           which pigz &>/dev/null
           if [ $? -eq 0 ]; then
-              sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | pigz $_pigz_opt -c - > "$annotate"
+              sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | pigz "$pigz_opt" -c - > "$annotate"
           else
-              sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | gzip $_gzip_opt -c - > "$annotate"
+              sort -u "$tmpdir"/hostsblock/"${annotate##*/}".tmp | gzip "$gzip_opt" -c - > "$annotate"
           fi
           [ -f "$annotate" ] && rm -f "$_v" -- "$tmpdir"/hostsblock/"${annotate##*/}".tmp
         ) &