How do I use command line arguments passed to a shell script that uses xargs?

Question

I have a script that will iterate a set of git checkouts and run a git command in each directory.

I now want to be able to pass a parameter to the shell script from the command line and have that parameter incorporated into the git command being run.

I am using the following script as a test (I've removed the git commands until I can see the parameter being displayed).

#!/usr/bin/env bash
find . -type d -exec test -e '{}/.git' ';' -print -prune | xargs -P 1 -I {} sh -c 'cd {}; echo `pwd` $1; echo ""'

If I run the command with a parameter, I'm expecting to see the name of the directory that contains a .git directory and the parameter.

I only get the directory name.

After a LOT of playing around, I ended up with this ...

#!/usr/bin/env bash
find . -type d -exec test -e '{}/.git' ';' -print -prune | BRANCH="$1" xargs -P 1 -I {} sh -c 'cd {}; echo `pwd` "${BRANCH}"; echo ""'

Is there a mechanism I have missed? Is there a "better" way to pass on the arguments?

Answer 1

From within your shell script you invoke another shell with an in-line script. Since you put this script between single quotes, the $1 is passed as is. The new shell you just launched, has its own set of parameters, which happen to be empty. So when parsing $1 it expands to nothing.

In your working example you assign your value to a new variable that is visible in the new shell.

---

If you're just trying to find all git repositories, you may also copy my all-git script below. Usage is simple: all-git <git command>, e.g. all-git status -bs

#!/bin/bash

for repo in `find $PWD -type d -name .git`
do
    repo=${repo%.git}
    ( 
        cd $repo
        echo "${repo%/}: " | sed -e "s#$HOME#~#"
        git "$@"
    )
done

Answer 2

find . -type d -exec test -e '{}/.git' ';' -print -prune | \
    xargs -P $(nproc) -I {} sh -c "cd \"{}\"; echo \"\$(pwd) $1\"; echo "

Should work, but also note that you can call an exported function.

OPT="$1"
function doGitWork {
    DIR="$1"
    cd "$DIR"
    echo "$(pwd) $OPT"
}
export -f doGitWork
find . -type d -exec test -e '{}/.git' ';' -print -prune | \
    xargs -P $(nproc) -I {} sh -c "doGitWork \"{}\";"

Answer 3

Using GNU Parallel it looks like this:

find . -type d -exec test -e '{}/.git' ';' -print -prune |
    parallel 'cd {}; echo $(pwd) {}; echo'

If you want to do git pull in all dirs that have a .git dir:

allgit() {
  find . -type d -name .git | 
      parallel --tagstring {//} "cd {//}; git $@"
}
allgit pull