(or "In dash, ... is not supported." when using
Also applies to RETURN and DEBUG.
#!/bin/sh trap 'Command failed with $?' ERR
Switch to a shell like
bash that does support the kind of trap you want:
#!/bin/bash trap 'Command failed with $?' ERR
Otherwise, rewrite the script to not rely on the trap.
You are trying to install a trap that is not supported by your current shell (
dash or POSIX
sh). There is no simple replacement. The script should be rewritten to avoid depending on the trap, or simply be run with a shell that supports it.
If you only intend to target shells that supports this feature, you can change the shebang to a shell that guarantees support, or ignore this warning.
You can use
# shellcheck disable=SC3000-SC4000 to ignore all such compatibility warnings.
ShellCheck is a static analysis tool for shell scripts. This page is part of its documentation.