Can gitconfig options be set conditionally?

The [include] section learned by git-config in v1.7.9 gets you most of the way there.

While it doesn't let you write runtime conditionals, it does give you a framework for refactoring your ~/.gitconfig into several parts: the shared section, and the env-specific sections. After that, you can symlink something like ~/.gitconfig.local to the relevant env-specific config file, and include ~/.gitconfig.local from ~/.gitconfig.

The symlinking part can be scripted and done automatically as part of your dotfiles' init script.

From the command line, that include path can be added via:

git config --global include.path '~/.gitconfig.local'

I use the quotes above specifically to prevent the shell from expanding ~ to an absolute path.

That adds the following section to your ~/.gitconfig:

[include]
    path = ~/.gitconfig.local

Here's a snippet from the git-scm book showing the general format:

[include]
    path = /path/to/foo.inc ; include by absolute path
    path = foo ; expand "foo" relative to the current file
    path = ~/foo ; expand "foo" in your $HOME directory

I don't think you can do this, but instead of maintaining your .gitconfig file, how about maintaining a script that generates your .gitconfig file? That way you can do whatever you want, based not only on variables but also on the output of commands and whatever...

like:

#!/bin/sh
if [ "$#" -eq 0 ]
then
    IS_REMOTE=
else
    case "$1" in
        remote)
            IS_REMOTE=1
            ;;
        local)
            IS_REMOTE=
            ;;
        *)
            echo "value $1 not supported" >&2
            ;;
    esac
fi

# config for both remote and local
git config --global color.ui true
git config --global alias.top '!pwd -L'

# config for remote
if [ "$IS_REMOTE" ]
then
    git config --global core.editor vim
    ...
else
    git config --global core.editor 'subl -n -w'
    ...
fi

So, if you call the script without parameters, or with the 'local' parameter, it will generate some configuration to your .gitconfig file, while if you pass the 'remote' parameter to it, it will generate some others.

You can conditionally include another Git config file based on your Git directory or branch in Git 2.13 and later.

Put your default configuration in file ~/.gitconfig as usual. At the end, conditionally include another configuration file:

[user]
    email = [email protected]
    name = John McGehee

# All work Git repositories are in a subdirectory of ~/work.
# All other Git repositories are outside ~/work.
[includeIf "gitdir:~/work/"]
    path = .gitconfig.work

Then, in ~/.gitconfig.work add or override configuration values you want when using a repository located in ~/work or any subdirectory thereof:

[user]
    email = [email protected]

You can observe the difference by changing to a Git directory under ~/work, and running:

git config user.email

Try the same command in a Git directory that is not under ~/work.

No, Git config does not support checks or conditional statements. But your underlying shell probably does, so you can use something like:

[core]
    editor = "if [[ $IS_REMOTE -eq 1 ]]; then ED='vim'; else ED='subl -n -w'; fi; $ED"

If you need to do something more complicated than that, you could just throw the shell code into a script, of course, like

[core]
    editor = "my_edi_script.sh"

with my_edit_script.sh containing something like:

#!/bin/bash
if [[ $IS_REMOTE -eq 1 ]]; then
    ED="vim"
else
    ED="subl -n -w"
fi

$ED some argument or other

Edit: The my_edit_script.sh would have to be in the $PATH, of course :)