Check if current directory is a Git repository

Copied from the bash completion file, the following is a naive way to do it

# Copyright (C) 2006,2007 Shawn O. Pearce <[email protected]>
# Conceptually based on gitcompletion (http://gitweb.hawaga.org.uk/).
# Distributed under the GNU General Public License, version 2.0.

if [ -d .git ]; then
  echo .git;
else
  git rev-parse --git-dir 2> /dev/null;
fi;

You could either wrap that in a function or use it in a script.

Condensed into a one line condition suitable for bash and zsh

[ -d .git ] && echo .git || git rev-parse --git-dir > /dev/null 2>&1

You can use:

git rev-parse --is-inside-work-tree

Which will print 'true' if you are in a git repos working tree.

Note that it still returns output to STDERR if you are outside of a git repo (and does not print 'false').

Taken from this answer: https://stackoverflow.com/a/2044714/12983