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Re: I thought >&- and > /dev/null were almost the same
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From: |
Chet Ramey |
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Subject: |
Re: I thought >&- and > /dev/null were almost the same |
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Date: |
Mon, 26 Nov 2001 09:34:57 -0500 |
> $ date > /dev/null
> $ date >&-
> date: write error: Bad file descriptor
These are not the same thing. The first provides `date' a valid file
descriptor 0 that is opened on /dev/null. The second closes file descriptor 0.
> $ echo o >&-
Echo doesn't check the validity of its output file descriptor; it just
tries to write. The return status indicates any errors.
$ echo o >&-
$ echo $?
1
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
( ``Discere est Dolere'' -- chet)
Chet Ramey, CWRU chet@po.CWRU.Edu http://cnswww.cns.cwru.edu/~chet/