Merge "A script to update the file contents with the command output."

#! /bin/bash

# Run given command application and update the contents of a given file.

# Will not change the file if its contents has not changed.

[[ $# -gt 1 ]] || { echo "Usage: ${0##*/} FILE COMMAND" >&2; exit 1; }

set -u

declare -r outfile="$1"

shift

if [[ ! -f $outfile ]]; then

	$@ >$outfile

	exit

fi

declare -r newout=${outfile}.new

$@ >$newout

rc=$?

if cmp -s $newout $outfile; then

	rm $newout

else

	mv -f $newout $outfile

fi

exit $rc