Published 2023-03-11. Last modified 2025-10-03.
Time to read: 2 minutes.

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I need to keep several hundred git repositories up-to-date. I have a directory tree of website repos, and a directory tree of code repos. Updating these trees was tedious until I wrote the initial version of the update script back in 2008.

Environment Variables

/etc/environment is a system-wide configuration file, which is sourced every time a user logs in. It is owned by root, so your account needs to be a member of the admin group, or you will have to use sudo to modify it.

The /etc/environment file in all of my systems defines two environment variables:

sites

Points to the root of the website directory tree

work

Points to the root of the code project tree

/etc/environment

export sites=/var/www
export work=/var/work

Now $sites and $work will be defined for all users every time they log in.

In addition, I define subordinate environment variables for each project in a file called $work/.evars

$work/.evars

export cadenzaHome=$work/cadenzaHome
export cadenzaCode=$cadenzaHome/cadenzaCode
export cadenzaDependencies=$cadenzaCode/cadenzaDependencies
export awslib_scala=$cadenzaDependencies/awslib_scala
export shoppingcart=$cadenzaDependencies/shoppingcart
export clients=$work/clients
export django=$work/django
export msp=$sites/www.mslinn.com
... 

$work/.evars is included by ~/.bashrc.

~/.bashrc

source $work/.evars

Switching Directories

The above environment variables allow me to easily move to a Git project directory without having to remember where it resides on the computer that I am currently using:

Shell

$ cd $clients

$ pwd
/var/work/clients 

Updating Git Directory Trees

I first wrote a Bash version of a command I called update, years later I wrote a multithreaded Ruby version that runs orders of magnitude faster for large directory trees. I called this version git-update; note that it requires a properly set up Ruby development environment.

The site and work environment variables are used by the update scripts.

update (Bash version)

#!/bin/bash

# Update all git directories below current directory or specified directory
# Skips directories that contain a file called .ignore
# See https://stackoverflow.com/a/61207488/553865

if [ "$( curl -sL -w "%{http_code}\n" https://www.github.com -o /dev/null )" != 200 ]; then
  echo "Cannot connect to GitHub"
  exit 2
fi

HIGHLIGHT="\e[01;34m"
NORMAL='\e[00m'

export PATH=${PATH/':./:'/:}
export PATH=${PATH/':./bin:'/:}
#echo "$PATH"

if [ -z "$1" ]; then
  ROOTS="$sites $work"
else
  ROOTS="$@"
fi

echo "Updating $ROOTS"
DIRS="$( find -L $ROOTS -type d \( -execdir test -e {}/.ignore \; -prune \) -o \( -execdir test -d {}/.git \; -prune -print \) )"

echo -e "${HIGHLIGHT}Scanning ${PWD}${NORMAL}"
for d in $DIRS; do
  cd "$d" > /dev/null || exit 2
  echo -e "\n${HIGHLIGHT}Updating `pwd`$NORMAL"
  git pull
  cd - > /dev/null || exit 3
done

The Ruby version of update is waaaay faster than the Bash version! Install the git-tree gem and get several git-related commands, including git-update. 💕💕💕

Most of the time I want to update everything in the standard Git directory trees, so for that no arguments are required:

Shell

$ git update
Updating /var/www /var/work
Updating /var/work/cadenzaHome/cadenzaCode/cadenzaDependencies/awslib_scala
Already up to date.

Updating /var/work/cadenzaHome/cadenzaCode/cadenzaDependencies/shoppingcart
Already up to date.

... 

It is also possible to specify the roots of one or more directory trees of git repositories:

Shell

$ git update /path/to/another/tree $my_gems $my_plugins
Updating /path/to/another/tree /mnt/f/work/ruby/my_gems /mnt/f/work/jekyll/my_plugins 

😁

I hope you find the update scripts to be as useful as I have!

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