how to use grep -E with bytes after the match

Question

I try to grep like this:

grep -E '(UNIQ_23A0E66922726E9|UNIQ_23A0E66D943CFF3)' xst.sql

however I need some bytes (not lines) before and after the match.

if i use both -E and -P i got:

grep: conflicting matchers specified

I want functionality like

grep -o -P '.{0,10}UNIQ_23A0E66922726E9.{0,10}' xst.sql 

but for all strings at once - in the example I have 2 but in reality I grep for 1000+.

Answer 1

-E tells GNU grep to use extended regular expressions (ERE), -P tells it to use Perl-compatible regular expressions (PCRE), which are a superset in functionality of ERE. Those are two different variants of the regex language, so indeed the options conflict with each other.

None of what you show needs PCRE though, so it seems you could just use

grep -o -E '.{0,10}(UNIQ_23A0E66922726E9|UNIQ_23A0E66D943CFF3).{0,10}' xst.sql

That would be a valid regex with the same meaning in PCRE, too. I'm not sure if there are performance differences between the ERE engine and the PCRE engine.