blah {
if ($1 == $null) echo -sec Info * /blah: insufficient parameters
else echo -a BLAH! $1-
}
You might also want to check the identifier $isid to see if the command was called as an identifier (
$blah(parameter1, parameter2, ...)) and change your response accordingly - ie. you wouldn't want to give an error message for /blah if it was called as $blah().
Also, it's important to use
if ($1 == $null) to check for the presence of a parameter and NOT use
if (!$1) since that will check that the parameter has a boolean false value, which could mean the parameter doesn't exist or is a 0 (so
/blah 0 would return an error if you used that).