diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
new file mode 100644
index 0000000..6a7de52
--- /dev/null
+++ b/.github/workflows/check.yml
@@ -0,0 +1,12 @@
+name: Check
+on:
+  push:
+  pull_request:
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: luizm/action-sh-checker@master
+        env:
+          SHELLCHECK_OPTS: -x
diff --git a/cpu.tmux b/cpu.tmux
index 576c206..40d8124 100755
--- a/cpu.tmux
+++ b/cpu.tmux
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
 source "$CURRENT_DIR/scripts/helpers.sh"
 
@@ -65,16 +65,19 @@ set_tmux_option() {
 
 do_interpolation() {
   local all_interpolated="$1"
-  for ((i=0; i<${#cpu_commands[@]}; i++)); do
+  for ((i = 0; i < ${#cpu_commands[@]}; i++)); do
     all_interpolated=${all_interpolated//${cpu_interpolation[$i]}/${cpu_commands[$i]}}
   done
   echo "$all_interpolated"
 }
 
 update_tmux_option() {
-  local option=$1
-  local option_value=$(get_tmux_option "$option")
-  local new_option_value=$(do_interpolation "$option_value")
+  local option
+  local option_value
+  local new_option_value
+  option=$1
+  option_value=$(get_tmux_option "$option")
+  new_option_value=$(do_interpolation "$option_value")
   set_tmux_option "$option" "$new_option_value"
 }
 
diff --git a/scripts/cpu_bg_color.sh b/scripts/cpu_bg_color.sh
index 0479e54..e072405 100755
--- a/scripts/cpu_bg_color.sh
+++ b/scripts/cpu_bg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 cpu_low_bg_color=""
@@ -19,13 +20,15 @@ get_bg_color_settings() {
 }
 
 print_bg_color() {
-  local cpu_percentage=$($CURRENT_DIR/cpu_percentage.sh | sed -e 's/%//')
-  local load_status=$(load_status $cpu_percentage "cpu")
-  if [ $load_status == "low" ]; then
+  local cpu_percentage
+  local load_status
+  cpu_percentage=$("$CURRENT_DIR"/cpu_percentage.sh | sed -e 's/%//')
+  load_status=$(load_status "$cpu_percentage" "cpu")
+  if [ "$load_status" == "low" ]; then
     echo "$cpu_low_bg_color"
-  elif [ $load_status == "medium" ]; then
+  elif [ "$load_status" == "medium" ]; then
     echo "$cpu_medium_bg_color"
-  elif [ $load_status == "high" ]; then
+  elif [ "$load_status" == "high" ]; then
     echo "$cpu_high_bg_color"
   fi
 }
@@ -34,4 +37,4 @@ main() {
   get_bg_color_settings
   print_bg_color
 }
-main
+main "$@"
diff --git a/scripts/cpu_fg_color.sh b/scripts/cpu_fg_color.sh
index 4f1e98d..3afb80e 100755
--- a/scripts/cpu_fg_color.sh
+++ b/scripts/cpu_fg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 cpu_low_fg_color=""
@@ -19,13 +20,15 @@ get_fg_color_settings() {
 }
 
 print_fg_color() {
-  local cpu_percentage=$($CURRENT_DIR/cpu_percentage.sh | sed -e 's/%//')
-  local load_status=$(load_status $cpu_percentage "cpu")
-  if [ $load_status == "low" ]; then
+  local cpu_percentage
+  local load_status
+  cpu_percentage=$("$CURRENT_DIR"/cpu_percentage.sh | sed -e 's/%//')
+  load_status=$(load_status "$cpu_percentage" "cpu")
+  if [ "$load_status" == "low" ]; then
     echo "$cpu_low_fg_color"
-  elif [ $load_status == "medium" ]; then
+  elif [ "$load_status" == "medium" ]; then
     echo "$cpu_medium_fg_color"
-  elif [ $load_status == "high" ]; then
+  elif [ "$load_status" == "high" ]; then
     echo "$cpu_high_fg_color"
   fi
 }
@@ -34,4 +37,4 @@ main() {
   get_fg_color_settings
   print_fg_color
 }
-main
+main "$@"
diff --git a/scripts/cpu_icon.sh b/scripts/cpu_icon.sh
index 2240640..99b9272 100755
--- a/scripts/cpu_icon.sh
+++ b/scripts/cpu_icon.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 # script global variables
@@ -21,13 +22,15 @@ get_icon_settings() {
 }
 
 print_icon() {
-  local cpu_percentage=$($CURRENT_DIR/cpu_percentage.sh | sed -e 's/%//')
-  local load_status=$(load_status $cpu_percentage "cpu")
-  if [ $load_status == "low" ]; then
+  local cpu_percentage
+  local load_status
+  cpu_percentage=$("$CURRENT_DIR"/cpu_percentage.sh | sed -e 's/%//')
+  load_status=$(load_status "$cpu_percentage" "cpu")
+  if [ "$load_status" == "low" ]; then
     echo "$cpu_low_icon"
-  elif [ $load_status == "medium" ]; then
+  elif [ "$load_status" == "medium" ]; then
     echo "$cpu_medium_icon"
-  elif [ $load_status == "high" ]; then
+  elif [ "$load_status" == "high" ]; then
     echo "$cpu_high_icon"
   fi
 }
@@ -36,4 +39,4 @@ main() {
   get_icon_settings
   print_icon "$1"
 }
-main
+main "$@"
diff --git a/scripts/cpu_percentage.sh b/scripts/cpu_percentage.sh
index 7816e0e..15190f0 100755
--- a/scripts/cpu_percentage.sh
+++ b/scripts/cpu_percentage.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 cpu_percentage_format="%3.1f%%"
@@ -25,9 +26,10 @@ print_cpu_percentage() {
   else
     if is_cygwin; then
       usage="$(cached_eval WMIC cpu get LoadPercentage | grep -Eo '^[0-9]+')"
+      # shellcheck disable=SC2059
       printf "$cpu_percentage_format" "$usage"
     else
-      load=`cached_eval ps -aux | awk '{print $3}' | tail -n+2 | awk '{s+=$1} END {print s}'`
+      load=$(cached_eval ps -aux | awk '{print $3}' | tail -n+2 | awk '{s+=$1} END {print s}')
       cpus=$(cpus_number)
       echo "$load $cpus" | awk -v format="$cpu_percentage_format" '{printf format, $1/$2}'
     fi
diff --git a/scripts/cpu_temp.sh b/scripts/cpu_temp.sh
index e645ac5..94fdfda 100755
--- a/scripts/cpu_temp.sh
+++ b/scripts/cpu_temp.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 cpu_temp_format="%2.0f"
@@ -11,7 +12,13 @@ print_cpu_temp() {
   cpu_temp_format=$(get_tmux_option "@cpu_temp_format" "$cpu_temp_format")
   cpu_temp_unit=$(get_tmux_option "@cpu_temp_unit" "$cpu_temp_unit")
   if command_exists "sensors"; then
-    ([ "$cpu_temp_unit" == F ] && sensors -f || sensors) | sed -e 's/^Tccd/Core /' | awk -v format="$cpu_temp_format$cpu_temp_unit" '/^Core [0-9]+/ {gsub("[^0-9.]", "", $3); sum+=$3; n+=1} END {printf(format, sum/n)}'
+    local val
+    if [[ "$cpu_temp_unit" == F ]]; then
+      val=$(sensors -f)
+    else
+      val=$(sensors)
+    fi
+    val | sed -e 's/^Tccd/Core /' | awk -v format="$cpu_temp_format$cpu_temp_unit" '/^Core [0-9]+/ {gsub("[^0-9.]", "", $3); sum+=$3; n+=1} END {printf(format, sum/n)}'
   fi
 }
 
diff --git a/scripts/cpu_temp_bg_color.sh b/scripts/cpu_temp_bg_color.sh
index 7cabaa2..c1fadd9 100755
--- a/scripts/cpu_temp_bg_color.sh
+++ b/scripts/cpu_temp_bg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 cpu_temp_low_bg_color=""
@@ -19,13 +20,15 @@ get_bg_color_settings() {
 }
 
 print_bg_color() {
-  local cpu_temp=$($CURRENT_DIR/cpu_temp.sh | sed -e 's/[^0-9.]//')
-  local cpu_temp_status=$(temp_status $cpu_temp)
-  if [ $cpu_temp_status == "low" ]; then
+  local cpu_temp
+  local cpu_temp_status
+  cpu_temp=$("$CURRENT_DIR"/cpu_temp.sh | sed -e 's/[^0-9.]//')
+  cpu_temp_status=$(temp_status "$cpu_temp")
+  if [ "$cpu_temp_status" == "low" ]; then
     echo "$cpu_temp_low_bg_color"
-  elif [ $cpu_temp_status == "medium" ]; then
+  elif [ "$cpu_temp_status" == "medium" ]; then
     echo "$cpu_temp_medium_bg_color"
-  elif [ $cpu_temp_status == "high" ]; then
+  elif [ "$cpu_temp_status" == "high" ]; then
     echo "$cpu_temp_high_bg_color"
   fi
 }
diff --git a/scripts/cpu_temp_fg_color.sh b/scripts/cpu_temp_fg_color.sh
index 73bb9bc..d5e4c6d 100755
--- a/scripts/cpu_temp_fg_color.sh
+++ b/scripts/cpu_temp_fg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 cpu_temp_low_fg_color=""
@@ -19,13 +20,15 @@ get_fg_color_settings() {
 }
 
 print_fg_color() {
-  local cpu_temp=$($CURRENT_DIR/cpu_temp.sh | sed -e 's/[^0-9.]//')
-  local cpu_temp_status=$(temp_status $cpu_temp)
-  if [ $cpu_temp_status == "low" ]; then
+  local cpu_temp
+  local cpu_temp_status
+  cpu_temp=$("$CURRENT_DIR"/cpu_temp.sh | sed -e 's/[^0-9.]//')
+  cpu_temp_status=$(temp_status "$cpu_temp")
+  if [ "$cpu_temp_status" == "low" ]; then
     echo "$cpu_temp_low_fg_color"
-  elif [ $cpu_temp_status == "medium" ]; then
+  elif [ "$cpu_temp_status" == "medium" ]; then
     echo "$cpu_temp_medium_fg_color"
-  elif [ $cpu_temp_status == "high" ]; then
+  elif [ "$cpu_temp_status" == "high" ]; then
     echo "$cpu_temp_high_fg_color"
   fi
 }
diff --git a/scripts/cpu_temp_icon.sh b/scripts/cpu_temp_icon.sh
index 85dfec0..93ad8df 100755
--- a/scripts/cpu_temp_icon.sh
+++ b/scripts/cpu_temp_icon.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 # script global variables
@@ -21,13 +22,15 @@ get_icon_settings() {
 }
 
 print_icon() {
-  local cpu_temp=$($CURRENT_DIR/cpu_temp.sh | sed -e 's/[^0-9.]//')
-  local cpu_temp_status=$(temp_status $cpu_temp)
-  if [ $cpu_temp_status == "low" ]; then
+  local cpu_temp
+  local cpu_temp_status
+  cpu_temp=$("$CURRENT_DIR"/cpu_temp.sh | sed -e 's/[^0-9.]//')
+  cpu_temp_status=$(temp_status "$cpu_temp")
+  if [ "$cpu_temp_status" == "low" ]; then
     echo "$cpu_temp_low_icon"
-  elif [ $cpu_temp_status == "medium" ]; then
+  elif [ "$cpu_temp_status" == "medium" ]; then
     echo "$cpu_temp_medium_icon"
-  elif [ $cpu_temp_status == "high" ]; then
+  elif [ "$cpu_temp_status" == "high" ]; then
     echo "$cpu_temp_high_icon"
   fi
 }
@@ -36,4 +39,4 @@ main() {
   get_icon_settings
   print_icon "$1"
 }
-main
+main "$@"
diff --git a/scripts/gpu_bg_color.sh b/scripts/gpu_bg_color.sh
index 9fd0c80..9b978fc 100755
--- a/scripts/gpu_bg_color.sh
+++ b/scripts/gpu_bg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 gpu_low_bg_color=""
@@ -19,13 +20,15 @@ get_bg_color_settings() {
 }
 
 print_bg_color() {
-  local gpu_percentage=$($CURRENT_DIR/gpu_percentage.sh | sed -e 's/%//')
-  local gpu_load_status=$(load_status $gpu_percentage "gpu")
-  if [ $gpu_load_status == "low" ]; then
+  local gpu_percentage
+  local gpu_load_status
+  gpu_percentage=$("$CURRENT_DIR"/gpu_percentage.sh | sed -e 's/%//')
+  gpu_load_status=$(load_status "$gpu_percentage" "gpu")
+  if [ "$gpu_load_status" == "low" ]; then
     echo "$gpu_low_bg_color"
-  elif [ $gpu_load_status == "medium" ]; then
+  elif [ "$gpu_load_status" == "medium" ]; then
     echo "$gpu_medium_bg_color"
-  elif [ $gpu_load_status == "high" ]; then
+  elif [ "$gpu_load_status" == "high" ]; then
     echo "$gpu_high_bg_color"
   fi
 }
@@ -34,4 +37,4 @@ main() {
   get_bg_color_settings
   print_bg_color
 }
-main
+main "$@"
diff --git a/scripts/gpu_fg_color.sh b/scripts/gpu_fg_color.sh
index 3fd6ad3..aa02cf6 100755
--- a/scripts/gpu_fg_color.sh
+++ b/scripts/gpu_fg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 gpu_low_fg_color=""
@@ -19,13 +20,15 @@ get_fg_color_settings() {
 }
 
 print_fg_color() {
-  local gpu_percentage=$($CURRENT_DIR/gpu_percentage.sh | sed -e 's/%//')
-  local gpu_load_status=$(load_status $gpu_percentage "gpu")
-  if [ $gpu_load_status == "low" ]; then
+  local gpu_percentage
+  local gpu_load_status
+  gpu_percentage=$("$CURRENT_DIR"/gpu_percentage.sh | sed -e 's/%//')
+  gpu_load_status=$(load_status "$gpu_percentage" "gpu")
+  if [ "$gpu_load_status" == "low" ]; then
     echo "$gpu_low_fg_color"
-  elif [ $gpu_load_status == "medium" ]; then
+  elif [ "$gpu_load_status" == "medium" ]; then
     echo "$gpu_medium_fg_color"
-  elif [ $gpu_load_status == "high" ]; then
+  elif [ "$gpu_load_status" == "high" ]; then
     echo "$gpu_high_fg_color"
   fi
 }
@@ -34,4 +37,4 @@ main() {
   get_fg_color_settings
   print_fg_color
 }
-main
+main "$@"
diff --git a/scripts/gpu_icon.sh b/scripts/gpu_icon.sh
index 7ce17ec..0bb52f4 100755
--- a/scripts/gpu_icon.sh
+++ b/scripts/gpu_icon.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 # script global variables
@@ -21,13 +22,15 @@ get_icon_settings() {
 }
 
 print_icon() {
-  local gpu_percentage=$($CURRENT_DIR/gpu_percentage.sh | sed -e 's/%//')
-  local gpu_load_status=$(load_status $gpu_percentage "gpu")
-  if [ $gpu_load_status == "low" ]; then
+  local gpu_percentage
+  local gpu_load_status
+  gpu_percentage=$("$CURRENT_DIR"/gpu_percentage.sh | sed -e 's/%//')
+  gpu_load_status=$(load_status "$gpu_percentage" "gpu")
+  if [ "$gpu_load_status" == "low" ]; then
     echo "$gpu_low_icon"
-  elif [ $gpu_load_status == "medium" ]; then
+  elif [ "$gpu_load_status" == "medium" ]; then
     echo "$gpu_medium_icon"
-  elif [ $gpu_load_status == "high" ]; then
+  elif [ "$gpu_load_status" == "high" ]; then
     echo "$gpu_high_icon"
   fi
 }
@@ -36,4 +39,4 @@ main() {
   get_icon_settings
   print_icon "$1"
 }
-main
+main "$@"
diff --git a/scripts/gpu_percentage.sh b/scripts/gpu_percentage.sh
index d78dce1..e68785e 100755
--- a/scripts/gpu_percentage.sh
+++ b/scripts/gpu_percentage.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 gpu_percentage_format="%3.1f%%"
diff --git a/scripts/gpu_temp.sh b/scripts/gpu_temp.sh
index ea9ed4d..05179a0 100755
--- a/scripts/gpu_temp.sh
+++ b/scripts/gpu_temp.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 gpu_temp_format="%2.0f"
@@ -20,7 +21,7 @@ print_gpu_temp() {
     return
   fi
   tempC=$(echo "$loads" | sed -nr 's/.*\s([0-9]+)C.*/\1/p' | awk '{sum+=$1; n+=1} END {printf "%5.3f", sum/n}')
-  if [ $gpu_temp_unit == "C" ]; then
+  if [ "$gpu_temp_unit" == "C" ]; then
     echo "$tempC" | awk -v format="${gpu_temp_format}C" '{sum+=$1} END {printf format, sum}'
   else
     echo "$tempC" | awk -v format="${gpu_temp_format}F" '{sum+=$1} END {printf format, sum*9/5+32}'
@@ -30,4 +31,4 @@ print_gpu_temp() {
 main() {
   print_gpu_temp
 }
-main
+main "$@"
diff --git a/scripts/gpu_temp_bg_color.sh b/scripts/gpu_temp_bg_color.sh
index 2bb5a70..57c566e 100755
--- a/scripts/gpu_temp_bg_color.sh
+++ b/scripts/gpu_temp_bg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 gpu_temp_low_bg_color=""
@@ -19,13 +20,15 @@ get_bg_color_settings() {
 }
 
 print_bg_color() {
-  local gpu_temp=$($CURRENT_DIR/gpu_temp.sh | sed -e 's/[^0-9.]//')
-  local gpu_temp_status=$(temp_status $gpu_temp)
-  if [ $gpu_temp_status == "low" ]; then
+  local gpu_temp
+  local gpu_temp_status
+  gpu_temp=$("$CURRENT_DIR"/gpu_temp.sh | sed -e 's/[^0-9.]//')
+  gpu_temp_status=$(temp_status "$gpu_temp")
+  if [ "$gpu_temp_status" == "low" ]; then
     echo "$gpu_temp_low_bg_color"
-  elif [ $gpu_temp_status == "medium" ]; then
+  elif [ "$gpu_temp_status" == "medium" ]; then
     echo "$gpu_temp_medium_bg_color"
-  elif [ $gpu_temp_status == "high" ]; then
+  elif [ "$gpu_temp_status" == "high" ]; then
     echo "$gpu_temp_high_bg_color"
   fi
 }
@@ -34,4 +37,4 @@ main() {
   get_bg_color_settings
   print_bg_color
 }
-main
+main "$@"
diff --git a/scripts/gpu_temp_fg_color.sh b/scripts/gpu_temp_fg_color.sh
index 4b15d7f..5dc5094 100755
--- a/scripts/gpu_temp_fg_color.sh
+++ b/scripts/gpu_temp_fg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 gpu_temp_low_fg_color=""
@@ -19,13 +20,15 @@ get_fg_color_settings() {
 }
 
 print_fg_color() {
-  local gpu_temp=$($CURRENT_DIR/gpu_temp.sh | sed -e 's/[^0-9.]//')
-  local gpu_temp_status=$(temp_status $gpu_temp)
-  if [ $gpu_temp_status == "low" ]; then
+  local gpu_temp
+  local gpu_temp_status
+  gpu_temp=$("$CURRENT_DIR"/gpu_temp.sh | sed -e 's/[^0-9.]//')
+  gpu_temp_status=$(temp_status "$gpu_temp")
+  if [ "$gpu_temp_status" == "low" ]; then
     echo "$gpu_temp_low_fg_color"
-  elif [ $gpu_temp_status == "medium" ]; then
+  elif [ "$gpu_temp_status" == "medium" ]; then
     echo "$gpu_temp_medium_fg_color"
-  elif [ $gpu_temp_status == "high" ]; then
+  elif [ "$gpu_temp_status" == "high" ]; then
     echo "$gpu_temp_high_fg_color"
   fi
 }
@@ -34,4 +37,4 @@ main() {
   get_fg_color_settings
   print_fg_color
 }
-main
+main "$@"
diff --git a/scripts/gpu_temp_icon.sh b/scripts/gpu_temp_icon.sh
index d4a162d..ece6487 100755
--- a/scripts/gpu_temp_icon.sh
+++ b/scripts/gpu_temp_icon.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 # script global variables
@@ -21,13 +22,15 @@ get_icon_settings() {
 }
 
 print_icon() {
-  local gpu_temp=$($CURRENT_DIR/gpu_temp.sh | sed -e 's/[^0-9.]//')
-  local gpu_temp_status=$(temp_status $gpu_temp)
-  if [ $gpu_temp_status == "low" ]; then
+  local gpu_temp
+  local gpu_temp_status
+  gpu_temp=$("$CURRENT_DIR"/gpu_temp.sh | sed -e 's/[^0-9.]//')
+  gpu_temp_status=$(temp_status "$gpu_temp")
+  if [ "$gpu_temp_status" == "low" ]; then
     echo "$gpu_temp_low_icon"
-  elif [ $gpu_temp_status == "medium" ]; then
+  elif [ "$gpu_temp_status" == "medium" ]; then
     echo "$gpu_temp_medium_icon"
-  elif [ $gpu_temp_status == "high" ]; then
+  elif [ "$gpu_temp_status" == "high" ]; then
     echo "$gpu_temp_high_icon"
   fi
 }
@@ -36,4 +39,4 @@ main() {
   get_icon_settings
   print_icon "$1"
 }
-main
+main "$@"
diff --git a/scripts/gram_bg_color.sh b/scripts/gram_bg_color.sh
index 224aab4..e8d95e6 100755
--- a/scripts/gram_bg_color.sh
+++ b/scripts/gram_bg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 gram_low_bg_color=""
@@ -19,13 +20,15 @@ get_bg_color_settings() {
 }
 
 print_bg_color() {
-  local gram_percentage=$($CURRENT_DIR/gram_percentage.sh | sed -e 's/%//')
-  local gram_load_status=$(load_status $gram_percentage "gram")
-  if [ $gram_load_status == "low" ]; then
+  local gram_percentage
+  local gram_load_status
+  gram_percentage=$("$CURRENT_DIR"/gram_percentage.sh | sed -e 's/%//')
+  gram_load_status=$(load_status "$gram_percentage" "gram")
+  if [ "$gram_load_status" == "low" ]; then
     echo "$gram_low_bg_color"
-  elif [ $gram_load_status == "medium" ]; then
+  elif [ "$gram_load_status" == "medium" ]; then
     echo "$gram_medium_bg_color"
-  elif [ $gram_load_status == "high" ]; then
+  elif [ "$gram_load_status" == "high" ]; then
     echo "$gram_high_bg_color"
   fi
 }
@@ -34,4 +37,4 @@ main() {
   get_bg_color_settings
   print_bg_color
 }
-main
+main "$@"
diff --git a/scripts/gram_fg_color.sh b/scripts/gram_fg_color.sh
index 387ae69..4f4d155 100755
--- a/scripts/gram_fg_color.sh
+++ b/scripts/gram_fg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 gram_low_fg_color=""
@@ -19,13 +20,15 @@ get_fg_color_settings() {
 }
 
 print_fg_color() {
-  local gram_percentage=$($CURRENT_DIR/gram_percentage.sh | sed -e 's/%//')
-  local gram_load_status=$(load_status $gram_percentage "gram")
-  if [ $gram_load_status == "low" ]; then
+  local gram_percentage
+  local gram_load_status
+  gram_percentage=$("$CURRENT_DIR"/gram_percentage.sh | sed -e 's/%//')
+  gram_load_status=$(load_status "$gram_percentage" "gram")
+  if [ "$gram_load_status" == "low" ]; then
     echo "$gram_low_fg_color"
-  elif [ $gram_load_status == "medium" ]; then
+  elif [ "$gram_load_status" == "medium" ]; then
     echo "$gram_medium_fg_color"
-  elif [ $gram_load_status == "high" ]; then
+  elif [ "$gram_load_status" == "high" ]; then
     echo "$gram_high_fg_color"
   fi
 }
@@ -34,4 +37,4 @@ main() {
   get_fg_color_settings
   print_fg_color
 }
-main
+main "$@"
diff --git a/scripts/gram_icon.sh b/scripts/gram_icon.sh
index f27aabe..04eb694 100755
--- a/scripts/gram_icon.sh
+++ b/scripts/gram_icon.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 # script global variables
@@ -21,13 +22,15 @@ get_icon_settings() {
 }
 
 print_icon() {
-  local gram_percentage=$($CURRENT_DIR/gram_percentage.sh | sed -e 's/%//')
-  local gram_load_status=$(load_status $gram_percentage "gram")
-  if [ $gram_load_status == "low" ]; then
+  local gram_percentage
+  local gram_load_status
+  gram_percentage=$("$CURRENT_DIR"/gram_percentage.sh | sed -e 's/%//')
+  gram_load_status=$(load_status "$gram_percentage" "gram")
+  if [ "$gram_load_status" == "low" ]; then
     echo "$gram_low_icon"
-  elif [ $gram_load_status == "medium" ]; then
+  elif [ "$gram_load_status" == "medium" ]; then
     echo "$gram_medium_icon"
-  elif [ $gram_load_status == "high" ]; then
+  elif [ "$gram_load_status" == "high" ]; then
     echo "$gram_high_icon"
   fi
 }
@@ -36,4 +39,4 @@ main() {
   get_icon_settings
   print_icon "$1"
 }
-main
+main "$@"
diff --git a/scripts/gram_percentage.sh b/scripts/gram_percentage.sh
index 9588b43..93dd7a7 100755
--- a/scripts/gram_percentage.sh
+++ b/scripts/gram_percentage.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 gram_percentage_format="%3.1f%%"
@@ -23,4 +24,4 @@ print_gram_percentage() {
 main() {
   print_gram_percentage
 }
-main
+main "$@"
diff --git a/scripts/helpers.sh b/scripts/helpers.sh
index a410a7e..6d72c46 100644
--- a/scripts/helpers.sh
+++ b/scripts/helpers.sh
@@ -1,10 +1,15 @@
+#!/usr/bin/env bash
+
 export LANG=C
 export LC_ALL=C
 
 get_tmux_option() {
-  local option="$1"
-  local default_value="$2"
-  local option_value="$(tmux show-option -qv "$option")"
+  local option
+  local default_value
+  local option_value
+  option="$1"
+  default_value="$2"
+  option_value="$(tmux show-option -qv "$option")"
   if [ -z "$option_value" ]; then
     option_value="$(tmux show-option -gqv "$option")"
   fi
@@ -16,33 +21,33 @@ get_tmux_option() {
 }
 
 is_osx() {
-  [ $(uname) == "Darwin" ]
+  [ "$(uname)" == "Darwin" ]
 }
 
 is_freebsd() {
-  [ $(uname) == "FreeBSD" ]
+  [ "$(uname)" == "FreeBSD" ]
 }
 
 is_openbsd() {
-  [ $(uname) == "OpenBSD" ]
+  [ "$(uname)" == "OpenBSD" ]
 }
 
 is_linux() {
-  [ $(uname) == "Linux" ]
+  [ "$(uname)" == "Linux" ]
 }
 
 is_cygwin() {
-  command -v WMIC &> /dev/null
+  command -v WMIC &>/dev/null
 }
 
 is_linux_iostat() {
   # Bug in early versions of linux iostat -V return error code
-  iostat -c &> /dev/null
+  iostat -c &>/dev/null
 }
 
 # is second float bigger or equal?
 fcomp() {
-  awk -v n1=$1 -v n2=$2 'BEGIN {if (n1<=n2) exit 0; exit 1}'
+  awk -v n1="$1" -v n2="$2" 'BEGIN {if (n1<=n2) exit 0; exit 1}'
 }
 
 load_status() {
@@ -50,9 +55,9 @@ load_status() {
   local prefix=$2
   medium_thresh=$(get_tmux_option "@${prefix}_medium_thresh" "30")
   high_thresh=$(get_tmux_option "@${prefix}_high_thresh" "80")
-  if fcomp $high_thresh $percentage; then
+  if fcomp "$high_thresh" "$percentage"; then
     echo "high"
-  elif fcomp $medium_thresh $percentage && fcomp $percentage $high_thresh; then
+  elif fcomp "$medium_thresh" "$percentage" && fcomp "$percentage" "$high_thresh"; then
     echo "medium"
   else
     echo "low"
@@ -60,12 +65,13 @@ load_status() {
 }
 
 temp_status() {
-  local temp=$1
+  local temp
+  temp=$1
   cpu_temp_medium_thresh=$(get_tmux_option "@cpu_temp_medium_thresh" "80")
   cpu_temp_high_thresh=$(get_tmux_option "@cpu_temp_high_thresh" "90")
-  if fcomp $cpu_temp_high_thresh $temp; then
+  if fcomp "$cpu_temp_high_thresh" "$temp"; then
     echo "high"
-  elif fcomp $cpu_temp_medium_thresh $temp && fcomp $temp $cpu_temp_high_thresh; then
+  elif fcomp "$cpu_temp_medium_thresh" "$temp" && fcomp "$temp" "$cpu_temp_high_thresh"; then
     echo "medium"
   else
     echo "low"
@@ -77,7 +83,7 @@ cpus_number() {
     if command_exists "nproc"; then
       nproc
     else
-      echo "$(( $(sed -n 's/^processor.*:\s*\([0-9]\+\)/\1/p' /proc/cpuinfo | tail -n 1) + 1 ))"
+      echo "$(($(sed -n 's/^processor.*:\s*\([0-9]\+\)/\1/p' /proc/cpuinfo | tail -n 1) + 1))"
     fi
   else
     sysctl -n hw.ncpu
@@ -85,12 +91,14 @@ cpus_number() {
 }
 
 command_exists() {
-  local command="$1"
-  command -v "$command" &> /dev/null
+  local command
+  command="$1"
+  command -v "$command" &>/dev/null
 }
 
 get_tmp_dir() {
-  local tmpdir="${TMPDIR:-${TMP:-${TEMP:-/tmp}}}"
+  local tmpdir
+  tmpdir="${TMPDIR:-${TMP:-${TEMP:-/tmp}}}"
   [ -d "$tmpdir" ] || local tmpdir=~/tmp
   echo "$tmpdir/tmux-$EUID-cpu"
 }
@@ -99,32 +107,41 @@ get_time() {
   date +%s.%N
 }
 
-get_cache_val(){
-  local key="$1"
+get_cache_val() {
+  local key
+  local timeout
+  local cache
+  key="$1"
   # seconds after which cache is invalidated
-  local timeout="${2:-2}"
-  local cache="$(get_tmp_dir)/$key"
+  timeout="${2:-2}"
+  cache="$(get_tmp_dir)/$key"
   if [ -f "$cache" ]; then
-    awk -v cache="$(head -n1 "$cache")" -v timeout=$timeout -v now=$(get_time) \
-      'BEGIN {if (now - timeout < cache) exit 0; exit 1}' \
-      && tail -n+2 "$cache"
+    awk -v cache="$(head -n1 "$cache")" -v timeout="$timeout" -v now="$(get_time)" \
+      'BEGIN {if (now - timeout < cache) exit 0; exit 1}' &&
+      tail -n+2 "$cache"
   fi
 }
 
-put_cache_val(){
-  local key="$1"
-  local val="${@:2}"
-  local tmpdir="$(get_tmp_dir)"
+put_cache_val() {
+  local key
+  local val
+  local tmpdir
+  key="$1"
+  val="$2"
+  tmpdir="$(get_tmp_dir)"
   [ ! -d "$tmpdir" ] && mkdir -p "$tmpdir" && chmod 0700 "$tmpdir"
-  echo "$(get_time)" > "$tmpdir/$key"
-  echo -n "$val" >> "$tmpdir/$key"
+  get_time >"$tmpdir/$key"
+  echo -n "$val" >>"$tmpdir/$key"
   echo -n "$val"
 }
 
-cached_eval(){
-  local command="$1"
-  local key="$(basename "$command")"
-  local val="$(get_cache_val "$key")"
+cached_eval() {
+  local command
+  local key
+  local val
+  command="$1"
+  key="$(basename "$command")"
+  val="$(get_cache_val "$key")"
   if [ -z "$val" ]; then
     put_cache_val "$key" "$($command "${@:2}")"
   else
diff --git a/scripts/ram_bg_color.sh b/scripts/ram_bg_color.sh
index 5a2a2c5..57ae7e7 100755
--- a/scripts/ram_bg_color.sh
+++ b/scripts/ram_bg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 ram_low_bg_color=""
@@ -19,13 +20,15 @@ get_bg_color_settings() {
 }
 
 print_bg_color() {
-  local ram_percentage=$($CURRENT_DIR/ram_percentage.sh | sed -e 's/%//')
-  local ram_load_status=$(load_status $ram_percentage "ram")
-  if [ $ram_load_status == "low" ]; then
+  local ram_percentage
+  local ram_load_status
+  ram_percentage=$("$CURRENT_DIR"/ram_percentage.sh | sed -e 's/%//')
+  ram_load_status=$(load_status "$ram_percentage" "ram")
+  if [ "$ram_load_status" == "low" ]; then
     echo "$ram_low_bg_color"
-  elif [ $ram_load_status == "medium" ]; then
+  elif [ "$ram_load_status" == "medium" ]; then
     echo "$ram_medium_bg_color"
-  elif [ $ram_load_status == "high" ]; then
+  elif [ "$ram_load_status" == "high" ]; then
     echo "$ram_high_bg_color"
   fi
 }
diff --git a/scripts/ram_fg_color.sh b/scripts/ram_fg_color.sh
index 6be021b..9d5a172 100755
--- a/scripts/ram_fg_color.sh
+++ b/scripts/ram_fg_color.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 ram_low_fg_color=""
@@ -19,13 +20,15 @@ get_fg_color_settings() {
 }
 
 print_fg_color() {
-  local ram_percentage=$($CURRENT_DIR/ram_percentage.sh | sed -e 's/%//')
-  local ram_load_status=$(load_status $ram_percentage "ram")
-  if [ $ram_load_status == "low" ]; then
+  local ram_percentage
+  local ram_load_status
+  ram_percentage=$("$CURRENT_DIR"/ram_percentage.sh | sed -e 's/%//')
+  ram_load_status=$(load_status "$ram_percentage" "ram")
+  if [ "$ram_load_status" == "low" ]; then
     echo "$ram_low_fg_color"
-  elif [ $ram_load_status == "medium" ]; then
+  elif [ "$ram_load_status" == "medium" ]; then
     echo "$ram_medium_fg_color"
-  elif [ $ram_load_status == "high" ]; then
+  elif [ "$ram_load_status" == "high" ]; then
     echo "$ram_high_fg_color"
   fi
 }
diff --git a/scripts/ram_icon.sh b/scripts/ram_icon.sh
index 9c3e454..5ad253b 100755
--- a/scripts/ram_icon.sh
+++ b/scripts/ram_icon.sh
@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 # script global variables
@@ -21,13 +22,15 @@ get_icon_settings() {
 }
 
 print_icon() {
-  local ram_percentage=$($CURRENT_DIR/ram_percentage.sh | sed -e 's/%//')
-  local ram_load_status=$(load_status $ram_percentage "ram")
-  if [ $ram_load_status == "low" ]; then
+  local ram_percentage
+  local ram_load_status
+  ram_percentage=$("$CURRENT_DIR"/ram_percentage.sh | sed -e 's/%//')
+  ram_load_status=$(load_status "$ram_percentage" "ram")
+  if [ "$ram_load_status" == "low" ]; then
     echo "$ram_low_icon"
-  elif [ $ram_load_status == "medium" ]; then
+  elif [ "$ram_load_status" == "medium" ]; then
     echo "$ram_medium_icon"
-  elif [ $ram_load_status == "high" ]; then
+  elif [ "$ram_load_status" == "high" ]; then
     echo "$ram_high_icon"
   fi
 }
@@ -36,4 +39,4 @@ main() {
   get_icon_settings
   print_icon "$1"
 }
-main
+main "$@"
diff --git a/scripts/ram_percentage.sh b/scripts/ram_percentage.sh
index df31c2c..25c85cd 100755
--- a/scripts/ram_percentage.sh
+++ b/scripts/ram_percentage.sh
@@ -1,14 +1,15 @@
 #!/usr/bin/env bash
 
-CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+CURRENT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
+# shellcheck source=scripts/helpers.sh
 source "$CURRENT_DIR/helpers.sh"
 
 ram_percentage_format="%3.1f%%"
 
 sum_macos_vm_stats() {
-  grep -Eo '[0-9]+' \
-  | awk '{ a += $1 * 4096 } END { print a }' 
+  grep -Eo '[0-9]+' |
+    awk '{ a += $1 * 4096 } END { print a }'
 }
 
 print_ram_percentage() {
@@ -20,23 +21,26 @@ print_ram_percentage() {
     # page size of 4096 bytes
     stats="$(cached_eval vm_stat)"
 
-    used_and_cached=$(echo "$stats" \
-      | grep -E "(Pages active|Pages inactive|Pages speculative|Pages wired down|Pages occupied by compressor)" \
-      | sum_macos_vm_stats \
+    used_and_cached=$(
+      echo "$stats" |
+        grep -E "(Pages active|Pages inactive|Pages speculative|Pages wired down|Pages occupied by compressor)" |
+        sum_macos_vm_stats
     )
 
-    cached=$(echo "$stats" \
-      | grep -E "(Pages purgeable|File-backed pages)" \
-      | sum_macos_vm_stats \
+    cached=$(
+      echo "$stats" |
+        grep -E "(Pages purgeable|File-backed pages)" |
+        sum_macos_vm_stats
     )
 
-    free=$(echo "$stats" \
-      | grep -E "(Pages free)" \
-      | sum_macos_vm_stats \
+    free=$(
+      echo "$stats" |
+        grep -E "(Pages free)" |
+        sum_macos_vm_stats
     )
 
-    used=$(($used_and_cached - $cached))
-    total=$(($used_and_cached + $free))
+    used=$((used_and_cached - cached))
+    total=$((used_and_cached + free))
 
     echo "$used $total" | awk -v format="$ram_percentage_format" '{printf(format, 100*$1/$2)}'
   fi