Git grep is a great search too, but I often find myself wanting to git grep for a term and then *replace* it too. With the "gsr" command, you can type in a search_term and a replace_term and it will search-->replace all matches. It's case-sensitive too.

git_search_replace_bash

# gsr = Git Search Replace
gsr() {
    search_string=$1
    replace_string=$2
    if [ -z $search_string ] || [ -z $replace_string ]
    then
        echo "-- Git Search & Replace (gsr)"
        echo "-- usage: gsr search_string replace_string"
    else
        git grep -l $search_string | xargs sed -i '' "s/$search_string/$replace_string/g"
        echo "Crushed it."
    fi
}