As for the workaround (without using non-portable -P
), you can temporary replace a new-line character with the different one and change it back, e.g.:
grep -o "_foo_" <(paste -sd_ file) | tr -d '_'
Basically it's looking for exact match _foo_
where _
means \n
(so __
= \n\n
). You don't have to translate it back by tr '_' '\n'
, as each pattern would be printed in the new line anyway, so removing _
is enough.