Regular Expressions 101

^start of line

Negative Lookahead(?!.*([abc]).*\1)

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

Group 1([abc])

Character Class[abc]

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

bthe literal b (98₁₀ / 142₈ / 62₁₆) (case sensitive)

cthe literal c (99₁₀ / 143₈ / 63₁₆) (case sensitive)

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

\1the text saved by group 1

Character Class[abc]{3}

{3}matches exactly 3 characters from the set below:

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

bthe literal b (98₁₀ / 142₈ / 62₁₆) (case sensitive)

cthe literal c (99₁₀ / 143₈ / 63₁₆) (case sensitive)

$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

^(?!.*([abc]).*\1)[abc]{3}$

New

abc
bac
cba
acb
cab

a
ab
ba
bc
ca
c
aba
acc
abb
cca
aab
abcd

abc
bac
cba
acb
cab

a
ab
ba
bc
ca
c
aba
acc
abb
cca
aab
abcd