Date: Mon, 04 Dec 2017 05:41:38 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 172862] sed(1) improperly deals with escape chars Message-ID: <bug-172862-8-hpVrMWzSiY@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-172862-8@https.bugs.freebsd.org/bugzilla/> References: <bug-172862-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=172862 Yuri Pankov <yuripv@gmx.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |yuripv@gmx.com --- Comment #3 from Yuri Pankov <yuripv@gmx.com> --- Despite what comment #1 says, sed does NOT match literal "\t" to a tab character outside [] as well -- quoting http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html: 9.3.2 BRE Ordinary Characters The interpretation of an ordinary character preceded by an unescaped <backslash> ('\\') is undefined. 9.4.2 ERE Ordinary Characters The interpretation of an ordinary character preceded by an unescaped <backslash> ( '\\' ) is undefined. There's an exception that is important here that <backslash> loses it's special meaning inside the bracket expression, so in your examples the bracket expression "[\t ]" correctly matches the 't' character and whitespace. Given the above, GNU sed actually violates the standard which defines the 's' command as the following: [2addr]s/BRE/replacement/flags ...so all BRE (ERE with -E) rules apply here. I would agree that *outside* of the bracket expression we could make "\t" match the tab character (that's what libtre does apparently) as it's more readable than inserting literal tab characters in RE, but inside the bracket expression GNU sed is clearly wrong, and our sed (through regex(3)) is doing the right thing. (I just hope I'm understanding everything correctly here, of course) -- You are receiving this mail because: You are the assignee for the bug.
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