xdiff

#!/usr/bin/env zsh

#
# INSTALLATION
#
# ln -s ${PWD}/xdiff $(brew --prefix)/bin/
# sudo ln -s ${PWD}/xdiff /usr/local/bin/
#

REPORT="$1" ; shift ;

# check command-line options

[ -z "$*" ] && {
	>&2 echo 'Usage: xdiff "<report>" <command(s)>' ;
	exit 1 ;
}

# check report command(s)

[ -z "${REPORT}" ] && { >&2 echo 'Missing report command(s)' ; exit 1 ; }

# capture the report output before & after
# running the actual commands, and diff it

BEFORE_EXEC="$(mktemp -t before)" ;
AFTER_EXEC="$(mktemp -t after)" ;

trap 'rm -f "${BEFORE_EXEC}" "${AFTER_EXEC}"' EXIT ;

> ${BEFORE_EXEC} ${=REPORT} ;
"$@" ; # run the actual command(s)
> ${AFTER_EXEC} ${=REPORT} ;

(
echo "--- \"${REPORT}\" (before) ;" ;
echo "+++ \"${REPORT}\" (after) ;" ;
) | colordiff > /dev/tty ;

(
colordiff --unified=20 --report-identical-files ${BEFORE_EXEC} ${AFTER_EXEC} ;
) | grep -E -v "(---|\+\+\+) ${TMPDIR}" > /dev/tty ;

# That's all Folks!