Save the following text in the file /home/username/.gitconfig

# Help for git-config
# https://www.kernel.org/pub/software/scm/git/docs/git-config.html
# Add a new global config option (global config option go into this file)
# like this: git config --global color.grep true
[user]
        name = Your Name
        email = your@email.com
        signingkey = 1A2B3C4D
[core]
        excludesfile = /home/username/.gitignore_global
[alias]
        undo-commit = reset --soft HEAD^
        logp = log -p --graph --word-diff
        logs = log --stat --graph
        wdiff = diff --word-diff
        signed-commit = commit --signoff --gpg-sign
        # If you want to use an external git tool other than kompare
        # use the command 'git difftool --tool-help' to see your
        # available options that can be used by git.
        kompare = difftool --tool kompare
        taginfo = tag -n
[grep]
        lineNumber = true
        patternType = perl
[color]
        grep = true
        diff = true
        branch = true
        status = true
[color "grep"]
        function = white
        linenumber = yellow
        filename = cyan
        match = red bold
[color "status"]
        header = yellow bold
        added = white bold
        changed = red bold
        untracked = cyan bold
[color "diff"]
        meta = yellow bold
        frag = magenta bold
        old = red bold
        new = green bold
        whitespace = red reverse
[log]
        decorate = full
[push]
        default = simple
[gpg]
        program = gpg2
[difftool]
        prompt = false