Regular Expressions 101

.any character (except for line terminators)

logthe literal text log (case sensitive)

Group 1(.[0-9]+)?

?repeats the group contents below at most once:

.any character (except for line terminators)

Character Class[0-9]+

+matches at least one character from the set below:

0-9one character from 0 (48₁₀) to 9 (57₁₀)

$end of line

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

.log(.[0-9]+)?$

New

POSITIVE TESTS
auth.log
auth.log.1
auth.log.99

NEGATIVE TESTS
auth.bak
auth.log.
auth.log.z
auth.log.zz

POSITIVE TESTS
auth.log
auth.log.1
auth.log.99

NEGATIVE TESTS
auth.bak
auth.log.
auth.log.z
auth.log.zz