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Re: \? is missing in "3.1.2.4 ANSI-C Quoting" in Bash Reference Manual
From: |
Chet Ramey |
Subject: |
Re: \? is missing in "3.1.2.4 ANSI-C Quoting" in Bash Reference Manual |
Date: |
Thu, 3 Sep 2015 15:07:05 -0400 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 |
On 9/2/15 11:46 PM, ziyunfei wrote:
> Sorry, I didn't understand your reply. What I'm saying is this: \? is shown
> in printf section:
>
> "Causes printf to expand backslash escape sequences in the corresponding
> argument, except that ‘\c’ terminates output, backslashes in ‘\'’, ‘\"’,
> and ‘\?’ are not removed, and octal escapes beginning with ‘\0’ may contain
> up to four digits.”
>
> but it isn't documented
> in https://www.gnu.org/software/bash/manual/html_node/ANSI_002dC-Quoting.html
> correspondingly
> after \’ and \”.
I guess I see what you're saying: that bash removes the backslash quoting
the `?' when processing $'...' but leaves backslashes escaping other
characters not listed in the description of $'...' unchanged. I can add
that to the documentation.
If that's not what you mean, I guess I don't understand. `printf %b'
expands one set of backslash escapes, and $'...' expands a slightly
different set, since they're trying to serve slightly different purposes
and have different origins. They're separate constructs and are documented
separately.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU chet@case.edu http://cnswww.cns.cwru.edu/~chet/