default
The default value for the option. For an option with argument it can be anything; for an option with no argument: it must be yes or no.
... witharg or noarg: declares if the option requires an argument or not.
description
A one-line str... on without argument, else returns with code one.
An option must be of the form --option, only charact... ption with argument, else returns with code one.
An option must be of the form --option=value, only c
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[[ $a == z* ]] # True if $a starts with an "z" (pattern matching).
[[ $a == "z*" ]] # Tr... ed within a [ ] construct.
See Example 27-11 for an application of this comparison operator.
----
-z
... string be quoted within the test brackets. Using an unquoted string with ! -z, or even just the unquo... see Example 7-6) normally works, however, this is an unsafe practice. Always quote a tested string.
=
