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On Tue, 2006-07-25 at 14:16 +0100, Neil Bothwick wrote: |
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> On Tue, 25 Jul 2006 09:26:52 -0300, Mauro Faccenda wrote: |
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> |
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> > > > You see? They cant be the same, because the closing "]" is needed |
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> > > > by /usr/bin[ and not by /usr/bin/test |
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> > > |
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> > > It's quite common for a program to change its behaviour according to |
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> > > the name used to run it. For example, zcat and gunzip are links to |
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> > > gzip, yet the three programs behave differently. |
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> > |
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> > but this isn't the case: |
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> |
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> I was disagreeing with the "cant be the same" comment. I know they are |
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> different files, but the slightly different behaviour is insufficient |
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> reason for that. Alexander asked why one was not a link to the other, I'd |
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> like to know too, but this isn't the reason. |
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For such a simple question, this sure is generating a lot of traffic :-) |
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The answer is simple: |
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'test' is a bash builtin. When a bash script executes 'test', it is |
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not /usr/bin/test that runs, but a function internal to bash. |
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/usr/bin/test/ is provided for environments that want to run bash |
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scripts that use test but bash is not the shell in use. |
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test and [ are not links to each other as they have different syntax |
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(the closing ]), so they cannot be the same command. If they were |
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linked, one of them would fail on execution with invalid syntax errors |
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alan |
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-- |
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