Fix snapshot script (#173)

services/snapshot.sh

@@ -5,7 +5,7 @@ outputFile="snapshot_$(date +%Y-%m-%d_%H-%M-%S).png"
 outputPath="$outputDir/$outputFile"
 mkdir -p "$outputDir"
 
-mode=$1
+mode=${1:-area}
 
 case "$mode" in
 active)
@@ -18,13 +18,14 @@ area)
     command="grimblast copysave area $outputPath"
     ;;
 *)
+    echo "Invalid option: $mode"
     echo "Usage: $0 {active|output|area}"
     exit 1
     ;;
 esac
 
 if eval "$command"; then
-    recentFile=$(ls -t "$outputDir"/snapshot_*.png | head -n 1)
+    recentFile=$(find "$outputDir" -name 'snapshot_*.png' -printf '%T+ %p\n' | sort -r | head -n 1 | cut -d' ' -f2-)
     notify-send "Grimblast" "Your snapshot has been saved." \
         -i video-x-generic \
         -a "Grimblast" \