2017-01-17 In the Unix shell, brackets appear in two ways: (1) for character classes in globbing, and (2) for condition testing in control flow. In the second form, they are no syntax elements of the Unix shell but a command name and its required last argument. [0] In the case of an `if', the shell does nothing but evaluate the exit status of the command after the `if', which in many cases will be the test(1) command (which is aliased to `[') but by no means has to. Understanding this is crucial to understanding shell programming. [0] https://debianforum.de/forum/viewtopic.php?f=34&t=163791#p1118314 http://marmaro.de/lue/ markus schnalke