bash script to use tree and exclude any files/directories git is ignoring

git-tree

#!/bin/bash
set -e
_=<<DOC
You can pass options to tree, but it's a bit bodgy, so you'll have to use -- before adding any directories if you pass any options.

If this script is available on your \$PATH then you can do \`git tree\` in repositories.
DOC

options=()
directories=()

# this is a bodge to make things like `git tree dir...` work so you don't have to do `git tree -- dir...` 
if [ "${1:0:1}" == "-" ]; then
    updating=options
else
    updating=directories
fi

# build options and directories lists
while [ "$#" -ne 0 ]; do
    part="$1"
    shift
    if [ "$updating" == options ] && [ "$part" == "--" ] ; then
        updating=directories
        continue
    fi
    if [ "$updating" == "options" ]; then
        options+=("$part")
    else
        directories+=("${part%%/}")
    fi
done

# default to the current directory if none were given
if [ "${#directories[@]}" -eq 0 ]; then
    directories=(".")
fi

# for each directory, run tree for it
for dir in "${directories[@]}"; do
    # this doesn't use the patterns in the 3 ignore file places as the patterns don't match up with those of tree
    # TODO(Code0x58): see about submodules. --recurse-submodules can be used so might have to git -C into each dir
    ignore=".git|"
    ignore+="$(cd "$dir" && git ls-files --ignored --exclude-standard --others --directory --cached -z \
        | sed -zr 's#/$##' \
        | tr "\\0" "|")"
    tree -a -I "${ignore::-1}" "${options[@]}" -- "$dir"
done