==in place of
(or "In dash, ... is not supported." when using
#!/bin/sh if [ $1 == "-n" ] then dry_run=1 fi
#!/bin/sh if [ $1 = "-n" ] then dry_run=1 fi
== is used for equality comparison in C-like languages, and is also supported by
[ .. ] and
dash only supports
= for equality comparison, so use that instead.
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.