From:	"Douglas G. Fowley" <fowley-dg AT salem DOT ge DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	SED problem
Date:	Tue, 30 Sep 1997 15:56:10 -0400
Organization:	GE Industrial Systems
Lines:	25
Message-ID:	<3431595A.5610@salem.ge.com>
NNTP-Posting-Host:	fowley.salem.ge.com
Mime-Version:	1.0
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

SED apparently ignores escape sequences in its regular expressions.
For example:

    C:\temp>echo this is a TAB \    \ >test

NOTE:  there is a single TAB character between the backslashes.

    C:\temp>sed -e "s/\t/<TAB>/" test
    <TAB>his is a TAB "     "

    C:\temp>sed --version
    GNU sed version 1.18

Is this a bug or am I doing something stupid?

To answer my own question, I hacked into the source.  In sed.c,
function compile_regex(), on line 1045, the code to recognize
'\b', '\f', '\t', and '\r' has been turned off.  When I turn
the code back on, re-make, and run the test again, I get:

    C:\temp>sed -e "s/\t/<TAB>/" test
    this is a TAB \<TAB>\ 

which is what I expect.  Anyone know why the SED code fragment
is turned off?

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