On 29/12/16 01:09, Peter & Kelly Passchier wrote: > Is this a bug? These both output "q=1" > > q=1 > [[ ((q==1)) ]] && echo q=1 > > q=0 > [[ ((q==1)) ]] && echo q=1 > > This looks like an incorrect use of [[/((. The correct phrasing would be:
q=1 ((q==1)) && echo q=1 q=0 ((q==1)) && echo q=1 By wrapping it in the [[ operator, instead of running ((...)) as a command, you're testing whether it is a string of nonzero length (and it always is, since you have it typed right there). The ((...)) operator alone is sufficient to make the test you want to make. It could also be phrased as: q=1 [[ $q -eq 1 ]] && echo q=1 q=0 [[ $q -eq 1 ]] && echo q=1 In the bash man page, under the SHELL GRAMMAR section is a description of the [[ operator, which should shed some further light on why this behaves as it does.
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