Bash scripts - Using ShellCheck to check .sh files

The goals of ShellCheck are

• To point out and clarify typical beginner's syntax issues that cause a shell to give cryptic error messages.
• To point out and clarify typical intermediate level semantic problems that cause a shell to behave strangely and counter-intuitively.
• To point out subtle caveats, corner cases and pitfalls that may cause an advanced user's otherwise working script to fail under future circumstances.

• https://github.com/koalaman/shellcheck
• demo: https://www.shellcheck.net/
• examples (untested yet) with Gitlab CI: https://github.com/koalaman/shellcheck/wiki/GitLab-CI

# ShellCheck     https://github.com/koalaman/shellcheck/wiki/GitLab-CI
# --> simple test job for GitLab (analyse testScript.sh):
test:
    image: koalaman/shellcheck-alpine:latest
    stage: test
    script: 
    - shellcheck testScript.sh

# ShellCheck     https://github.com/koalaman/shellcheck/wiki/GitLab-CI
#                https://git-scm.com/docs/git-ls-files
# --> a CI job that will lint all shell scripts in a git repository:
test:
    image: koalaman/shellcheck-alpine:latest
    stage: test
    before_script:
    - apk update
    - apk add git
    script:
    - git ls-files --exclude='*.sh' --ignored | xargs shellcheck