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Re: echo "-e" produces no outputs
From: |
Chet Ramey |
Subject: |
Re: echo "-e" produces no outputs |
Date: |
Sun, 19 Jul 2009 21:07:20 -0400 |
User-agent: |
Thunderbird 2.0.0.22 (Macintosh/20090605) |
Stephane CHAZELAS wrote:
> 2009-07-17, 13:09(-06), Eric Blake:
>> According to Huang Tao on 7/17/2009 9:46 AM:
>>> I'm not sure whether it is a bug
>>> how can i echo the text string "-e" barely ( or "-n", "-E")
>>> i tried
>>> $echo "-e"
>>> $echo '-e'
>>> and some other inputs, all of which produced no outputs.
>> Instead of using echo (which POSIX itself admits is fraught with
>> portability problems), use printf:
>>
>> printf -- '-e\n'
> [...]
>
> Note that it's a known non POSIX-conformance of bash.
>
> POSIX is explicit that
>
> echo -e
>
> Should output "-e\n".
That's why bash has the `xpg_echo' option. You can build bash in such
a way that it's always enabled.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
Chet Ramey, ITS, CWRU chet@case.edu http://cnswww.cns.cwru.edu/~chet/