hooks/pre-receive: expr: not found

Question

I host git on my server and have webhooks that run commands like

branch=$(expr "$refname" : "refs/heads/\(.*\)")

This works perfectly with SSH git pushes but when trying to use the HTTPS protocol I get the error

hooks/pre-receive: expr: not found

I guess this is because the script runs as www-data when using https.

Any ideas how to solve this problem?

Answer 1

If this is the same server, you should check that the PATH environment variable is set appropriately when this hook is invoked from your HTTP server; it's likely to be missing /bin or /usr/bin (whichever stores your expr command).

---

That said, there's no need for expr here at all. Assuming that the value in $refname starts with refs/heads :

# Delete the leading refs/heads/ from refname to get branch
branch=${refname#refs/heads/}

Otherwise:

# Delete everything up to and including the first instance of refs/heads/
branch=${refname#*refs/heads/}

If you want to check whether refname contains refs/heads/ at all, this is most easily done in bash (your script starting with #!/bin/bash ):

if [[ $refname = *refs/heads/ ]]; then
  branch=${refname#*/refs/heads/}
else
  # refname does not match the pattern
  branch=
fi

If you are in fact using bash, you can actually use even more similar code:

refname_re='refs/heads/(.*)'
if [[ $refname =~ $refname_re ]]; then
  branch=${BASH_REMATCH[1]}
fi