I found the issue. '.' does not match the new line. so the following works well. $ echo 'changequote([,])patsubst(good[] bad,\`\(.\| \)*'\\\'',a\&b)'|m4 agood badb
On Sun, Jul 5, 2020 at 11:06 AM Ice Ninja <aeron.e.w...@gmail.com> wrote: > According to > https://www.gnu.org/software/findutils/manual/html_node/find_html/emacs-regular-expression-syntax.html > > GNU extensions are supported: > > 1. ‘\w’ matches a character within a word > 2. ‘\W’ matches a character which is not within a word > 3. ‘\<’ matches the beginning of a word > 4. ‘\>’ matches the end of a word > 5. ‘\b’ matches a word boundary > 6. ‘\B’ matches characters which are not a word boundary > 7. ‘\`’ matches the beginning of the whole input > 8. ‘\'’ matches the end of the whole input > > However if I try using \` and \' in patsubst, it fails to find the match. > > $ echo 'changequote()changequote([,])debugmode()traceon[]patsubst(good[] > bad,\`.*'\\\'',a\&b)'|m4 > m4trace: -1- patsubst([good > bad], [\`.*\'], [a\&b]) -> [good > bad] > good > bad > > \< \> seems to be supported. > $ echo 'changequote()changequote([,])debugmode()traceon[]patsubst(good[] > bad,\<.*\>,a\&b)'|m4 > m4trace: -1- patsubst([good > bad], [\<.*\>], [a\&b]) -> [agoodb > abadb] > agoodb > abadb > > $ m4 --version > m4 (GNU M4) 1.4.18 > Copyright (C) 2016 Free Software Foundation, Inc. > License GPLv3+: GNU GPL version 3 or later < > http://gnu.org/licenses/gpl.html>. > This is free software: you are free to change and redistribute it. > There is NO WARRANTY, to the extent permitted by law. > > Written by Rene' Seindal. > $ cat /etc/redhat-release > Fedora release 26 (Twenty Six) > > Thanks > >
