More stable and deterministic polybar launch script

polybar/.config/polybar/launch.sh

@@ -1,33 +1,46 @@
 #!/bin/sh
 
-# Terminate already running bar instances
-killall -q polybar
-
-# Wait until the processes have been shut down
-while pgrep -u "$(id -u)" -x polybar >/dev/null; do sleep 1; done
-
-# Launch polybar
-#polybar main -c $HOME/.config/polybar/config &
-
-# Set Monitors
-#xrandr --output HDMI1 --auto --left-of LVDS1
-
-POLY_IFACES="$(ip link show | awk '/^[0-9]+:/ {sub(/:/,"",$2); print $2}')"
+set -e
+
+# If at least one polybar process is running send a SIGTERM to all:
+# - Give a grace period of N cycles to all processes to terminate gracefully
+# - When the grace period is expired, send a SIGKILL to all
+cycle=0
+while pgrep -u "$(id -u)" -x polybar >/dev/null
+do
+  if [ $cycle -eq 0 ]; then
+    # Terminate already running bar instances
+    pkill -U "$(id -u)" -15 polybar
+  elif [ $cycle -eq 4 ]; then
+    # At the 5th cylcle SIGKILL
+    pkill -U "$(id -u)" -9 polybar
+  fi
+  sleep 1
+  cycle=$((cycle + 1))
+done
+unset cycle
 
-for NET_IFACE in $POLY_IFACES ; do
+NET_IFACES="$(ip link show | awk '/^[0-9]+:/ {sub(/:/,"",$2); print $2}')"
+for NET_IFACE in $NET_IFACES ; do
   case $NET_IFACE in
     wlp* ) POLY_WLP=$NET_IFACE ;;
     enp* ) POLY_ENP=$NET_IFACE ;;
   esac
 done
+unset NET_IFACES
 
-HWMON_BASEDIR="$(find "/sys/devices/platform/coretemp.0/hwmon/" -maxdepth 1 -type d -name 'hwmon*' | tail -n +2 | head -1)"
-POLY_HWMON="$HWMON_BASEDIR"/temp1_input
+HWMON_MODULE="/sys/devices/platform/coretemp.0/hwmon/"
+if [ -d "$HWMON_MODULE" ]; then
+  HWMON_BASEDIR="$(find "$HWMON_MODULE" -maxdepth 1 -type d -name 'hwmon*' | tail -n +2 | head -1)"
+  POLY_HWMON="$HWMON_BASEDIR"/temp1_input
+  unset HWMON_BASEDIR
+fi
+unset HWMON_MODULE
 
 if type "xrandr"; then
   for m in $(xrandr --query | grep " connected" | cut -d" " -f1); do
     POLY_WLP=$POLY_WLP POLY_ENP=$POLY_ENP POLY_HWMON=$POLY_HWMON MONITOR=$m polybar main -c "$HOME/.config/polybar/config" &
   done
-else
-  POLY_WLP=$POLY_WLP POLY_ENP=$POLY_ENP POLY_HWMON=$POLY_HWMON MONITOR=$m polybar main -c "$HOME/.config/polybar/config" &
 fi
+
+unset POLY_WLP POLY_ENP POLY_HWMON