Question

When initialize a new git repository (on Linux/Ubuntu), we use:

# What this doing:
GIT_DIR=myproject.git git init  
#The above line will output: Initialized empty Git Repo...

cd myproject.git  
git --bare update-server-info  
cp hooks/post-update.sample hooks/post-update

The first line “GIT_DIR=…” confuses me, it seems bash will get a env variable and git use the first to init the new project, BUT how? Who can explain this little magic?

Answer 1

This is a feature of Bash and other Bourne-compatible shells:

VAR=val cmd

runs cmd with VAR set to val and otherwise the environment of the shell itself.

Try running the following commands:

printenv
export FOO=bar
printenv | grep '^FOO='
FOO=baz printenv | grep '^FOO='