Regular Expressions 101

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/
(:.+)(?(1)Cool!)
/
gm
1st Capturing Group
(:.+)
: matches the character : with index 5810 (3A16 or 728) literally (case sensitive)
.
matches any character (except for line terminators)
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
Conditional
(?(1)Cool!)
Conditionally matches one of two options depending on whether the 1st capturing group matched
If condition is met, match the following regex
Cool!
Cool!
matches the characters Cool! literally (case sensitive)
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
gm

Test String

Substitution

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