On 17 August 2014 08:36, Cameron Simpson <cs@xxxxxxxxxx> wrote: > On 16Aug2014 14:44, Mike Wright <mike.wright@xxxxxxxxxxxxxx> wrote: >> >> I'm trying to write a simple script that if provided an argument, uses >> that, or if nothing is provided, uses a predefined string. > > > This is general shell stuff, not bash specific. > >> if [ -n $# ] > > > This is always true. Even "0" is a nonempty string. > > Test [ $# -gt 0 ] instead. > > Though it's a matter of preference I'd prefer [ $# = 0 ] or [ $# != 0 ] tests unless you really need one of the numeric comparisons. The reason (and it doesn't actually apply for $#, hence matter of preference) is that if you have somehow ended up with a string rather than a number (e.g. an error from wc or something) then you have to think about what your comparison is going to do for that case, whereas the =! and == comparisons will do what you expect. If you do need -gt, -lt and the rest then (except for $#) it's best to check what you've got is a number first. -- imalone http://ibmalone.blogspot.co.uk -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org
