Regular Expressions 101

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/
^(?<prefix>-{0,2}[A-Za-z\s_\-:]+)?(?<version>\d+)(?<sufix>.+)$
/
gm
^ asserts position at start of a line
Named Capture Group prefix
(?<prefix>-{0,2}[A-Za-z\s_\-:]+)?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
-
matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
Match a single character present in the list below
[A-Za-z\s_\-:]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
A-Z matches a single character in the range between A (index 65) and Z (index 90) (case sensitive)
a-z matches a single character in the range between a (index 97) and z (index 122) (case sensitive)
\s matches any whitespace character (equivalent to [\r\n\t\f\v ])
_ matches the character _ with index 9510 (5F16 or 1378) literally (case sensitive)
\- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
: matches the character : with index 5810 (3A16 or 728) literally (case sensitive)
Named Capture Group version
(?<version>\d+)
\d
matches a digit (equivalent to [0-9])
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
Named Capture Group sufix
(?<sufix>.+)
.
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)
$ asserts position at the end of a line
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