diff-apply

#!/usr/bin/env bash

# Apply a command ($1) to two files ($2, $3) and diff the results
#
# The command should be provided in a format suitable to be passed to GNU parallel.
#
# Example:
#
# $ diff-apply sort file1 file2

cmd="$1"; shift
f1="$1"; shift
f2="$1"; shift

t1="$(mktemp)"
t2="$(mktemp)"
finish() {
  rm -f "$t1" "$t2"
}
trap finish EXIT

echo "$f1" | parallel --env PATH "$cmd" > "$t1"
echo "$f2" | parallel --env PATH "$cmd" > "$t2"
diff "$t1" "$t2"