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Re: short-circuit test ... -a ...
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From: |
Eric Blake |
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Subject: |
Re: short-circuit test ... -a ... |
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Date: |
Thu, 23 Aug 2007 15:25:52 -0600 |
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Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.6) Gecko/20070728 Thunderbird/2.0.0.6 Mnenhy/0.7.5.666 |
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According to Yakov Lerner on 8/23/2007 11:24 AM:
>
> Description:
> x=; test "$x" != "" -a "$x" -le 60
> prints error:
> bash: test: : integer expression expected
> Shall not this *silently* short-circuit to false after
> subexpressio n '"$x" != ""' evaluated
> to false ?
According to POSIX,
http://www.opengroup.org/onlinepubs/009695399/utilities/test.html, there
is no requirement for -a to be short-circuiting, and the results of
testing more than 4 arguments (you had 7) is unspecified. So there is no
compelling reason to change the current behavior.
If you want short-circuiting, do this instead:
x=; test "$x" != "" && test "$x" -le 60
- --
Don't work too hard, make some time for fun as well!
Eric Blake ebb9@byu.net
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