diff-dotfiles.sh

#!/usr/bin/env bash

# Keep this script in a directory with the master copy of your dotfiles.
# For example, keep this script in a dotfiles folder in your Dropbox.
# Run this script to diff your dotfiles between the master copy (in the pwd)
# and the dotfiles installed at ~.

show_help() {
    cat <<EOF
Usage: diff-dotfiles.sh OPTION [filename]

If <filename> is present, diff that dotfile. Otherwise, diff all of them,
showing the diff between the repository version and the version currently
installed.

The default output is a unified diff, so you should be able to do things like
$ ./diff-dotfiles.sh .foo | patch ~/.foo

OPTIONS:
 -h  Show help and exit.
 -m  Use meld to diff and edit file(s).
 -l  List files that are different.

Ex:
./diff-dotfiles.sh -l
./diff-dotfiles.sh -m .gitignore
EOF
    exit 0
}

# Parse command line options.
difftool="diff -u --color"
list_files=0
while getopts hml opt; do
    case $opt in
        h)
            show_help
            ;;
        m)
            difftool="meld"
            shift
            ;;
        l)
            list_files=1
            shift
            ;;
        *)
            show_help
            ;;
    esac
done


# If listing files, do that.
if [[ $list_files -eq 1 ]]; then
    echo "The following files have differences:"
    for filename in .[!.]*; do
        if [[ "$filename" == ".git" ]]; then
            continue
        fi

        diff $filename ~/$filename > /dev/null
        if [[ $? -ne 0 ]]; then
            echo "  $filename"
        fi
    done
    exit 0
fi

# Meld with no args should do a directory diff.
if [[ "$difftool" == "meld" && -z "$1" ]]; then
    $difftool ~ ./
    exit 0
fi

# Diff either the whole dir or just our files, with the correct difftool.
if [[ ! -z "$1" ]]; then
    $difftool ~/$1 $1
else
    for filename in .[!.]*; do
        if [[ "$filename" == ".git" ]]; then
            continue
        fi
        $difftool ~/$filename $filename
        echo -e "\n"
    done
fi