--default
is undefined(or any other option)
#!/bin/ksh
set --default
Switch to a shell that supports these options, such as Ksh:
#!/bin/ksh
set --default
Your script uses a shell feature not supported by the shebang. Either rewrite the script to be portable, or change the shebang to explicitly require a shell like Ksh.
Most shell specific set
flags are hard to emulate in
POSIX, so use your best judgement as to whether you can make do without
them, or if you should require a shell that supports them.
None
ShellCheck is a static analysis tool for shell scripts. This page is part of its documentation.