relint

System: Slackware Linux (version 15.0)
CPUs: Intel(R) Core(TM) i5-3230M CPU @2.60GHz
GPU: Mesa DRI Intel(R) HD Graphics 4000

Elisp regexp mistake finder.

M-x package-install RET relint RET

bash-5.1$ cd /tmp
bash-5.1$ git clone -q https://github.com/wryun/es-shell.git
bash-5.1$ emacs -batch --eval "(package-initialize)" -l relint \
> -f relint-batch es-shell/examples/es-mode.el
es-shell/examples/es-mode.el:13:10-11: Ineffective string escape ‘\'’
es-shell/examples/es-mode.el:21:7-8: In es-font-lock-keywords: Unescaped literal ‘$’ (pos 0)
  "$\\w*"
es-shell/examples/es-mode.el:21:7-8: Ineffective string escape ‘\$’
relint: 3 problems.
bash-5.1$