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On Monday 24 September 2007, Duncan wrote: |
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> Donnie Berkholz <dberkholz@g.o> posted: |
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> > For tests, pick a style |
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> > [[ ]] or [ ] and stick with it. The [[ ]] one is pretty nice because it |
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> > generally doesn't require quotes, so the code looks a lot cleaner. |
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> |
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> Can you point me (and anyone else that may be interested) to a nice |
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> explanation of the difference? |
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|
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i use `man bash` myself ... |
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> I've always wondered why [[ ]] is |
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> considered "better" than [ ] for tests. |
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as Donnie pointed out, it handles quoting sanely ... it also allows for |
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extended bash logic tests (like matching and regexps) as well as your |
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standard logic operators |
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|
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fails: |
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f="moo cow with space" |
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[ ${f} = blah ] |
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works: |
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[[ ${f} == blah ]] |
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|
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wildcards: |
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[[ ${f} == *moo* ]] |
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|
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C logic operators (rather than crappy shell '-a' / '-o' / etc...): |
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[[ moo == foo || moo == moo && blah == doit ]] |
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-mike |
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