And errors out expectedly using dash or ash, very nice POSIX Sh compliant shells:

$ ./foo.sh
./foo.sh: line 5: [: bar: integer expression expected

So the lessons here are twofold:

• Always use shellcheck to check your shell code
  
• Never use Bash or rely on Bash(isms). Always prefer POSIX Sh

@movq@www.uninformativ.de Yes I feel your pain 🙄