On Thu, Oct 26, 2017 at 11:12:16PM +1100, David Margerison wrote: > > That's a fair point, but the documentation of the 'if' statement in 'man bash' > will make that immediately clear to anyone who cares to read it. > You must regularly deal with different sorts of people than I do :-)
> The [[ test, the $? parameter, and the =0 test are three separate > redundancies that are not needed here to achieve the desired result. > > So the code you gave is a good illustration of how $? works, but should > also be identified as a bad example of how to correctly achieve the goal > in this case. > That all depends on the definition of "correct" for a given situation. If I were writing example code for my students that meant to illustrate something I would likely choose something different than if I were writing for a production environment with a team consisting of experienced developers. > Because in shell syntax, the 'if' statement is conceived and intended > to be used directly with any/all commands. > > So I believe that good guidance should make that point clearly, and that > is my reason for writing again here, to present that alternative. > > Also, some shells do not support [[ and its syntax differs from [ and 'test' > in various fun ways. > This is a good point, but the given example started with "#!/bin/bash" indicating that the author likely intended to use bash-specific constructs. Personally, when I write specifically for bash (as opposed to more generally for sh) I favor [[ over [ and test. Regards, -Roberto -- Roberto C. Sánchez
