On 27Apr2013 16:41, Mike Wright mike.wright@mailinator.com wrote: | 04/27/2013 03:49 PM, Cameron Simpson wrote: | >On 26Apr2013 09:12, Patrick O'Callaghan pocallaghan@gmail.com wrote: | >| On Fri, 2013-04-26 at 15:36 +0300, Cristian Sava wrote: | >| > [ "z$WEBALIZER_CRON" != "zyes" ] && exit 0 [...] | >| The "z$Foo" != "zbar" style is idiomatic in Shell scripts. I think it's | >| to ensure portability between Shells with slightly different expression | >| rules. | > | >In particular it avoids issues where $WEBALIZER_CRON looks like a test | >operator such as "-z" or something unfortunate. | | Also there may be situations where $SOME_VAR evaluates to null. | Then a test looks like [ != "something" ] which is guaranteed to | break.
It's quoted. That will stop it vanishing.