mkls

#!/usr/bin/env bash
set -euo pipefail
# 
# generate a list and diff against self
# useful inside Makefile where script creates a bunch of files
# and we only need to run the next step if there are new file names
# for example, this Makefile only runs step2 if we haven't run `make` today
#     init.log:
#       touch txt/$`date +%F`
#       mkls init.log 'txt/*'
#     step2.log: init.log
#       echo hi > txt/`date +%F`
#       mkls step2.log
# LOG:
#  20190718 - init
#  20191024 - outsource to mkifdiff

[[ $# -lt 1 ]] && echo "USAGE: $0 dirlist.txt '/list/*/files'\n find -iname '*thing*' | $0 dirlist.txt" && exit 1
! command -v mkifdiff >/dev/null && echo "missing mkifdiff; cannot run $0!" && exit 1
CMPFILE="$1"; shift

# write list to TMPFILE - either have a pattern to ls or piping from e.g. find
if [ $# -ge 1 ]; then
   ls -d "$@" | mkifdiff "$CMPFILE"
else
   echo "DEPRECATED: use mkifdiff for pipe compare" >&2
   tty >/dev/null  && echo "need to pipe to $0; cmd | $0 $1" && exit 1
   cat | mkifdiff "$CMPFILE"
fi