Add time-until script

packages/time-until.nix

@@ -0,0 +1,27 @@
+{ pkgs }:
+
+pkgs.writeShellApplication {
+  name = "time-until";
+
+  runtimeInputs = with pkgs; [ bc ];
+
+  text = ''
+    # Based on https://github.com/sdaschner/dotfiles/blob/master/bin/time-until.
+    set +o nounset
+
+    if [[ "$1" == "" ]]; then
+      echo "Usage: ''${0##*/} <date-string>"
+      echo " Example: ''${0##*/} 'tomorrow 06:00'"
+      exit 2
+    fi
+
+    set -o nounset
+
+    secsUntil=$(( $(date +%s -d "$*") - $( date +%s ) ))
+    minutesUntil=$(bc <<< "scale=1; $secsUntil/60")
+    hoursUntil=$(bc <<< "scale=2; $secsUntil/3600")
+    date=$(date -d "$*")
+
+    echo "$hoursUntil hours (or $minutesUntil mins) until $date"
+  '';
+}