How to quickly find all git repos under a directory

Question

The following bash script is slow when scanning for .git directories because it looks at every directory. If I have a collection of large repositories it takes a long time for find to churn through every directory, looking for .git. It would go much faster if it would prune the directories within repos, once a .git directory is found. Any ideas on how to do that, or is there another way to write a bash script that accomplishes the same thing?

#!/bin/bash  # Update all git directories below current directory or specified directory  HIGHLIGHT="\e[01;34m" NORMAL='\e[00m'  DIR=. if [ "$1" != "" ]; then DIR=$1; fi cd $DIR>/dev/null; echo -e "${HIGHLIGHT}Scanning ${PWD}${NORMAL}"; cd ->/dev/null  for d in `find . -name .git -type d`; do   cd $d/.. > /dev/null   echo -e "\n${HIGHLIGHT}Updating `pwd`$NORMAL"   git pull   cd - > /dev/null done 

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Specifically, how would you use these options? For this problem, you cannot assume that the collection of repos is all in the same directory; they might be within nested directories.

top   repo1   dirA    dirB      dirC         repo1 

Answer 1

Check out Dennis' answer in this post about find's -prune option:

How to use '-prune' option of 'find' in sh?

find . -name .git -type d -prune 

Will speed things up a bit, as find won't descend into .git directories, but it still does descend into git repositories, looking for other .git folders. And that 'could' be a costly operation.

What would be cool is if there was some sort of find lookahead pruning mechanism, where if a folder has a subfolder called .git, then prune on that folder...

That said, I'm betting your bottleneck is in the network operation 'git pull', and not in the find command, as others have posted in the comments.

Answer 2

Here is an optimized solution:

#!/bin/bash # Update all git directories below current directory or specified directory # Skips directories that contain a file called .ignore  HIGHLIGHT="\e[01;34m" NORMAL='\e[00m'  function update {   local d="$1"   if [ -d "$d" ]; then     if [ -e "$d/.ignore" ]; then        echo -e "\n${HIGHLIGHT}Ignoring $d${NORMAL}"     else       cd $d > /dev/null       if [ -d ".git" ]; then         echo -e "\n${HIGHLIGHT}Updating `pwd`$NORMAL"         git pull       else         scan *       fi       cd .. > /dev/null     fi   fi   #echo "Exiting update: pwd=`pwd`" }  function scan {   #echo "`pwd`"   for x in $*; do     update "$x"   done }  if [ "$1" != "" ]; then cd $1 > /dev/null; fi echo -e "${HIGHLIGHT}Scanning ${PWD}${NORMAL}" scan *