Regular Expressions 101

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/
(.{1,80}\S)(?:[\r\n\f\v ]+|$)
/
gm
1st Capturing Group
(.{1,80}\S)
.
matches any character (except for line terminators)
{1,80} matches the previous token between 1 and 80 times, as many times as possible, giving back as needed (greedy)
\S matches any non-whitespace character (equivalent to [^\r\n\t\f\v ])
Non-capturing group
(?:[\r\n\f\v ]+|$)
1st Alternative
[\r\n\f\v ]+
Match a single character present in the list below
[\r\n\f\v ]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
\r matches a carriage return (ASCII 13)
\n matches a line-feed (newline) character (ASCII 10)
\f matches a form-feed character (ASCII 12)
\v matches any vertical whitespace character
matches the character with index 3210 (2016 or 408) literally (case sensitive)
2nd Alternative
$
$ 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

Substitution

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