I've got a variable in my shell script for a git branch name, that might contain a Jira issue key. I want to extract the issue from the variable if it matches my regexp.

A Jira issue can be some letters, followed by a dash, followed by some numbers. My script for this is the following:

#!/bin/bash

echo "pre-receive HOOK"

while read oldrev newrev refname
do
    echo "Refname is"
    echo $refname //refs/heads/XS-1141

    echo "Old revision is"
    echo $oldrev

    echo "New revision is"
    echo $newrev

    re="[A-Z] -\d "
    echo "checking if branch name contains a JIRA issue (format XX-1111, SRS-1 or similar)"
    if [[ $refname =~ $re ]]; then echo ${BASH_REMATCH[1]}; fi;
done

My input is in the comment there in the script (refs/heads/XS-1141) and the output of that is the BASH_REMATCH empty.

I'd like to achieve two things here:

1. Find out if the branch name contains a Jira issue
2. Extract that Jira issue to a variable

How can I do that?

CodePudding user response：

Your re has no groups, so you need to use ${BASH_REMATCH[0]}

Also, you need to replace \d with [0-9] as \d digit matching pattern is not supported by POSIX ERE.

So you can use

#!/bin/bash
refname='refs/heads/XS-1141'
re="[A-Z] -[0-9] "
echo "checking if branch name contains a JIRA issue (format XX-1111, SRS-1 or similar)"
if [[ $refname =~ $re ]]; then echo ${BASH_REMATCH[0]}; fi;

See the online demo.

The ${BASH_REMATCH[0]} holds the XS-1141 value here.