A simple shell script to loop through all sub-directories of current directory and perform a 'git pull' on each. This assumes all sub-directories are git repositories.

update_repos.sh

#!/usr/bin/env bash

base_dir=$PWD

# Loop through directories
for dir in */ ; do
    [ -L "${dir%/}" ] && continue
    this_dir=$base_dir/$dir
    cd $this_dir
    echo "-->$this_dir"
    if [ -d .git ]; then
        git pull
    else
        echo "Not a git directory."
    fi;
done