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On Nov 8, 2011 9:02 AM, "Claudio Roberto França Pereira" <spideybr@×××××.com> |
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wrote: |
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> |
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> What about [[? I've seen scripts using [[ instead of only one [. Whats |
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the point/difference? |
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AFAIK [[ was originally a bash-specific built-in command that provides more |
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functionality than /bin/[, but can still use /bin/['s convoluted syntax. |
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The two converged quickly, though. IIRC [ is now also a bash built-in, |
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which still maintains compatibility with /bin/[ |
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An example: |
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[ $VAR ] will produce an error if VAR is empty or unset, but [[ $VAR ]] |
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won't. |
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(for the former, you have to put double quotes around, e.g., [ "$VAR"] ) |
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Rgds, |
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