Update journal.sh to use nix

journal.sh

@@ -1,23 +1,23 @@
-#!/usr/bin/env zsh
+#!/usr/bin/env nix-shell
+#! nix-shell -i zsh
+#! -p zsh coreutils gpg
 
 # ====
 # journal.sh
 # Manages a simple journaling system.
 #
-# Written for Mac
-# 
-# Uses GNU coreutils, gdate, gsed, etc.
+# Uses nix to manage all deps
 # ====
 
 set_dates() {
-  nowtime=$(gdate "+%H:%M") || exit
-  day=$(gdate "+%A" -d "$*") || exit
-  daynum=$(gdate "+%e" -d "$*") || exit
-  month=$(gdate "+%m" -d "$*") || exit
-  year=$(gdate "+%Y" -d "$*") || exit
-  date=$(gdate "+%Y-%m-%d" -d "$*") || exit
+  nowtime=$(date "+%H:%M") || exit
+  day=$(date "+%A" -d "$*") || exit
+  daynum=$(date "+%e" -d "$*") || exit
+  month=$(date "+%m" -d "$*") || exit
+  year=$(date "+%Y" -d "$*") || exit
+  date=$(date "+%Y-%m-%d" -d "$*") || exit
 
-  date_path=$(gdate "+%Y/%m" -d "$*") || exit
+  date_path=$(date "+%Y/%m" -d "$*") || exit
   journal_prefix=~/code/txt/cal
   file="$journal_prefix/$date_path/$date.txt"
 }
@@ -40,7 +40,6 @@ case "$arg" in
       $PAGER "$file"
     fi
 
-
     exit 0
 esac
 
@@ -53,7 +52,7 @@ if [ ! -f "$file" ]; then
 
   printf "%0.s=" {1..13} >> $file
   printf "\n" >> $file
-  cal -h "$month" "$year" | gsed "0,/$daynum/{s//XX/}" >> $file
+  cal -h "$month" "$year" | sed "0,/$daynum/{s//XX/}" >> $file
   truncate -s -1 $file
   
   printf "\n$day\n" >> $file