Date: Sat, 16 Nov 2019 22:15:50 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 242013] matching back references works only some of the time Message-ID: <bug-242013-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242013 Bug ID: 242013 Summary: matching back references works only some of the time Product: Base System Version: 12.0-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: bin Assignee: bugs@FreeBSD.org Reporter: khellman@mcprogramming.com Matching back references according to re_format(7): Finally, there is one new type of atom, a back reference: ‘\’ followed by a non-zero decimal digit d matches the same sequence of characters matched by the dth parenthesized subexpression (numbering subexpressions by the positions of their opening parentheses, left to right), so that (e.g.) ‘\([bc]\)\1’ matches ‘bb’ or ‘cc’ but not ‘bc’. does not always seem to work. For instance, I would expect all of these to print the single input line: $ echo '#20#20' | sed -n -E -e '/(#|0x)(..)\1\2/p' $ echo '#2020#' | sed -n -E -e '/(#|0x)(..)\2\1/p' $ echo '#202020' | sed -n -E -e '/(#|0x)(..)20\2/p' #202020 $ echo '#202020' | sed -n -E -e '/(#|0x)(..)\2(20)/p' $ echo '#202020' | sed -n -E -e '/(#|0x)(..)(20)\2/p' #202020 $ echo '#202020' | sed -n -E -e '/(#|0x)(..)..\2/p' #202020 $ echo '#20#20' | sed -n -E -e '/(#|0x)(..).\2/p' #20#20 Additionally, gsed(1) equivalent invocations work as expected. -- You are receiving this mail because: You are the assignee for the bug.help
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