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Alan McKinnon wrote: |
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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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> |
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> For such a simple question, this sure is generating a lot of traffic :-) |
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> |
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> The answer is simple: |
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> |
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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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True. Same for [. |
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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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Nothing to argue here. |
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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. |
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That's not true. /usr/bin/[ and /usr/bin/test *COULD* be the |
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same commands. If a program is invoked, it gets in $0 the name |
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the user has used to call the program. Depending on this name/value, |
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the program could behave differntly. |
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> If they were |
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> linked, one of them would fail on execution with invalid syntax errors |
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Wrong. |
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Alexander Skwar |
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-- |
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The politician is someone who deals in man's problems of adjustment. |
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To ask a politician to lead us is to ask the tail of a dog to lead the dog. |
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-- Buckminster Fuller |
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-- |
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