Regular Expressions 101

^start of line

Group 1(\S+)

\S+any non-whitespace character, repeated at least once

\s+any whitespace character, repeated at least once

Negative Lookahead(?!\1)

\1the text saved by group 1

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

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.

25 tokens

Regular Expression

^(\S+)\s+(?!\1).*

New

43,186 43,186
296,531 296,531
108086 108086
abcdef abcdef
Capture This
497,802 497,802
200,062 300,062
Not Same
202232 252232
4,324,452 4,324,452

43,186 43,186
296,531 296,531
108086 108086
abcdef abcdef
Capture This
497,802 497,802
200,062 300,062
Not Same
202232 252232
4,324,452 4,324,452