Fix maybe-alert not sending notifications to my computer anymore.

Apparently --urgency=low is too low for a popup on my laptop 🤷

Also, touch it up to use better practices.

maybe-alert

@@ -5,32 +5,36 @@
 #
 # Run notify-send if the command takes longer than $1 seconds
 
-if [[ -z $DISPLAY ]]; then
+
+set -euo pipefail
+[[ -n "${DEBUG:-}" ]] && set -x
+
+if [[ -z "${DISPLAY}" ]]; then
     exec "${@:2}"
 fi
 
 max=$1
 command="${*:2}"
-begin=$(date +%s)
+begin="$(date +%s)"
 alerted=0
 
 _alert() {
     local exit_status=$?
 
     if ((!alerted)); then
         alerted=1
-        local end=$(date +%s)
+        local end="$(date +%s)"
 
         local elapsed=$((end - begin))
-        if [[ $exit_status != 0 || $elapsed -ge $max ]]; then
-            icon=$([[ $exit_status == 0 ]] && echo info || echo error)
-            summary="Command took $(display-seconds $elapsed) to complete."
+        if [[ ${exit_status} != 0 || ${elapsed} -ge ${max} ]]; then
+            icon=$([[ ${exit_status} == 0 ]] && echo info || echo error)
+            summary="Command took $(display-seconds "${elapsed}") to complete."
 
-            notify-send --urgency=low -i "$icon" "$summary" "$command"
+            notify-send -i "${icon}" "${summary}" "${command}"
         fi
     fi
 
-    exit $exit_status
+    exit ${exit_status}
 }
 trap '_alert' INT QUIT TERM EXIT