Regular Expressions 101

^start of line

Negative Lookahead(?!.*\.\d{4}\.ext$)

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

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d{4}a digit, repeated exactly 4 times

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

extthe literal text ext (case sensitive)

$end of line

.+any character (except for line terminators), repeated at least once

$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

^(?!.*\.\d{4}\.ext$).+$

New

this is a 9876 file name .1234.ext
thisisa9876filename .4321.ext
thisisa9876filename.123.ext
thisisa9876filename.12345.ext
this is a 9876 file name.txe

Substitution

this is a 9876 file name .1234.ext
thisisa9876filename .4321.ext
thisisa9876filename.123.ext
thisisa9876filename.12345.ext
this is a 9876 file name.txe