Use environment variable in github action if - github-actions

Question

I'm trying to use an environment variable in an if condition in github actions like so:
name: Worfklow
on:
push
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout#v1
- name: EXIT step
if: $GITHUB_REF == 'specific-branch'
run: exit 1
I want to exit if the current branch is equal to a specific branch.
Unfortunately, the github actions console displays an error:
Unexpected symbol: '$GITHUB_REF'
I can use $GITHUB_REF in a run: (where it contains the current branch), but not in an if:. What am I doing wrong?

Answer 1

Though the original problem had been solved without environment vars, I'd like to share how it can be used with if conditions.
jobs:
deploy:
runs-on: ubuntu-latest
steps:
- name: Set env BRANCH
run: echo "BRANCH=$(echo $GITHUB_REF | cut -d'/' -f 3)" >> $GITHUB_ENV
- name: Set env NEED
run: |
if [[ $BRANCH == 'master' && $GITHUB_EVENT_NAME == 'push' ]]; then
echo "NEED=true" >> "$GITHUB_ENV"
else
echo "NEED=false" >> "$GITHUB_ENV"
fi
- name: Skip Deploy?
if: env.NEED != 'true'
run: echo "Only pushing to 'master' causes automatic deployment"
...
The first two steps set 2 env variables, the third step demonstrates what syntax you need to follow to use these vars in if conditions.

Answer 2

do it like this:
if: github.ref == 'specific-branch'
reference branch conditional

Answer 3

If you want to check an environment variable on job-level (refer to Github context), you can do like this:
env:
MY_VAR: Dummy
jobs:
build:
name: Build
runs-on: ubuntu-latest
outputs:
myVar: ${{ steps.init.outputs.myVar }}
steps:
- name: Environment variables to output
id: init
run: |
echo "myVar=${{ env.MY_VAR }}" >> $GITHUB_OUTPUT
And use it in another job:
second_job:
name: Second Job
needs: build
if: needs.build.outputs.myVar == 'Dummy'

Answer 4

You can use some restrictions on the push section of the action
on:
push:
branches:
- '*' # matches every branch that doesn't contain a '/'
- '*/*' # matches every branch containing a single '/'
- '**' # matches every branch
- '!master' # excludes master
This answer was taken from this stack overflow question