On 2014-11-12 00:03, Marcin Zajączkowski wrote: > On 2014-11-11 23:54, Glenn Jackman wrote: >> Marcin, applying this to the 2-variable question: >> >> $ test "$SSH_TTY$SSH_CLIENT"; and echo "not empty"; or echo "unset or empty" >>> unset or empty >>> $ ssh localhost >>> [...] >>> $ test "$SSH_TTY$SSH_CLIENT"; and echo "not empty"; or echo "unset or >>> empty" >>> not empty > > Nice trick Gleen. That works fine when as a substitution of `or` > operator (just one variable set makes the test return `true`).
Sorry, Gleen -> Glenn. Marcin >> On Tue, Nov 11, 2014 at 5:51 PM, Glenn Jackman <jack...@pythian.com> wrote: >> >>> I suspect what is happening (this is true in bash, I'm speculating about >>> fish) is that an unset variable is substituted with nothing (not the empty >>> string, but with nothing). Then the `test` command receives exactly one >>> argument: "-n". When `test` is given a single argument, the result is true >>> if that argument is not empty. This is true for the string "-n". >>> >>> So another way to write the test is simply >>> >>> if test $NOT_SET_VARIABLE; ... >>> >>> >>> Demo >>> >>> $ set -q foobar >>>> $ test $foobar; and echo "not empty"; or echo "unset or empty" >>>> unset or empty >>>> $ set foobar "" >>>> $ test $foobar; and echo "not empty"; or echo "unset or empty" >>>> unset or empty >>>> $ set foobar abc >>>> $ test $foobar; and echo "not empty"; or echo "unset or empty" >>>> not empty >>> >>> >>> >>> >>> On Tue, Nov 11, 2014 at 5:33 PM, Greg Reagle <greg.rea...@umbc.edu> wrote: >>> >>>> That's very interesting. I get the same problem. I don't think >>>> anything is wrong with your code. I think something fishy is going on >>>> with fish, but I don't know what. It looks like it might even be a bug >>>> in fish. I would expect test -n to be the opposite of test -z, but that >>>> is not true sometimes. >>>> >>>> There are a few workarounds. >>>> >>>> I find that test -z works fine. >>>> >>>> Another way to test a variable is >>>> if test ab"$variable"cd = abcd; echo zero; else; echo non-zero; end >>>> >>>> -- >>>> http://www.fastmail.fm - Access all of your messages and folders >>>> wherever you are >>>> >>>> >>>> >>>> ------------------------------------------------------------------------------ >>>> Comprehensive Server Monitoring with Site24x7. >>>> Monitor 10 servers for $9/Month. >>>> Get alerted through email, SMS, voice calls or mobile push notifications. >>>> Take corrective actions from your mobile device. >>>> >>>> http://pubads.g.doubleclick.net/gampad/clk?id=154624111&iu=/4140/ostg.clktrk >>>> _______________________________________________ >>>> Fish-users mailing list >>>> Fish-users@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/fish-users >>>> >>> >>> >>> >>> -- >>> *Glenn Jackman* >>> Senior Software Developer >>> >>> *Pythian - Love your data* >>> jack...@pythian.com >>> Tel: +1 613 565 8696 Ext. 1478 >>> Mobile: +1 613 808 4984 >>> www.pythian.com >>> >> >> >> > > -- http://blog.solidsoft.info/ - Working code is not enough ------------------------------------------------------------------------------ Comprehensive Server Monitoring with Site24x7. Monitor 10 servers for $9/Month. Get alerted through email, SMS, voice calls or mobile push notifications. Take corrective actions from your mobile device. http://pubads.g.doubleclick.net/gampad/clk?id=154624111&iu=/4140/ostg.clktrk _______________________________________________ Fish-users mailing list Fish-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/fish-users
