git diff file in column mode

gdiff

#!/usr/bin/env bash

# diff file at given path to committed version.
# Use colordiff, if installed 
# e.g. gdiff my-file.c

PREFERRED_DIFFER="colordiff"
command -v ${PREFERRED_DIFFER} >/dev/null 2>&1 || PREFERRED_DIFFER="diff"

if [[ -z "${1}" ]]; then
    echo "Usage: ${0} <path to file>"
fi
FILE_TO_DIFF_PATH="${1}"

## Comparison version e.g. HEAD~1, default to 0
VERSION=0

if [[ -n "${2}" ]]; then
    VERSION="${2}"
fi

# Must provide path to file in git command, add './' if required
if [[ "$(dirname "${1}")" == "." ]]; then
    FILE_TO_DIFF_PATH="./${1}"
fi

printf "\nUsing ${PREFERRED_DIFFER}, on ${FILE_TO_DIFF_PATH}\n\n"

# set the diff column width for the current users setup
CURRENT_COLS=$(tput cols)
${PREFERRED_DIFFER} -yW"${CURRENT_COLS}" <(git show HEAD~${VERSION}:"${FILE_TO_DIFF_PATH}") "${FILE_TO_DIFF_PATH}"