diff-logs

#!/bin/bash
#
# This is the diff-logs utility for diff'ing log files.
#
# See usage instructions below.
#
set -eu
set -o pipefail

lib="$(dirname "$(command -v "$0" || true)")"
pyscript="$lib/diff-logs.py"
difftool="${DIFFTOOL:-diff}"

if [ $# -eq 0 ]; then
    "$pyscript" <&0;
elif [ $# -eq 2 ]; then
    case $difftool in diff) args='--color=auto' ;; *) args= ;; esac
    # shellcheck disable=SC2086,SC2248,SC2312
    $difftool $args <("$pyscript" < "$1") <("$pyscript" < "$2");
else
    echo "Usage: $0 < FILE.log            # Print log file diff-friendly" >&2
    echo "       $0 FILE1.log FILE2.log   # Invoke \$DIFFTOOL (e.g. diff)" >&2
    exit 1
fi