Regular Expressions 101

1st Alternative^(?!.*STRING99).*(*SKIP)

^start of line

Negative Lookahead(?!.*STRING99)

.*any character (except for line terminators), repeated any number of times

STRING99the literal text STRING99 (case sensitive)

.*any character (except for line terminators), repeated any number of times

(*SKIP)acts like (*PRUNE), but the next unanchored match attempt starts where (*SKIP) was reached instead of at the next subject character

2nd Alternative[^\d\n]+

Negated Character Class[^\d\n]+

+matches at least one character outside the set below:

\da digit

\na line-feed (newline) character (ASCII 10)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^(?!.*STRING99).*(*SKIP)|[^\d\n]+

New

a1 2b c3d
a1 STRING99 2b c3d