Regular Expressions 101

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/
^(.+)(?<!\\)((?:\\\\)*)(\!\=|(?<!\!|\<|\>)=|\<\=|\>\=)(.+)$
/
gm
^ asserts position at start of a line
1st Capturing Group
(.+)
.
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)
Negative Lookbehind
(?<!\\)
Assert that the Regex below does not match
\\ matches the character \ with index 9210 (5C16 or 1348) literally (case sensitive)
2nd Capturing Group
((?:\\\\)*)
Non-capturing group
(?:\\\\)*
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\\ matches the character \ with index 9210 (5C16 or 1348) literally (case sensitive)
\\ matches the character \ with index 9210 (5C16 or 1348) literally (case sensitive)
3rd Capturing Group
(\!\=|(?<!\!|\<|\>)=|\<\=|\>\=)
1st Alternative
\!\=
\! matches the character ! with index 3310 (2116 or 418) literally (case sensitive)
\= matches the character = with index 6110 (3D16 or 758) literally (case sensitive)
2nd Alternative
(?<!\!|\<|\>)=
Negative Lookbehind
(?<!\!|\<|\>)
Assert that the Regex below does not match
1st Alternative
\!
\! matches the character ! with index 3310 (2116 or 418) literally (case sensitive)
2nd Alternative
\<
\< matches the character < with index 6010 (3C16 or 748) literally (case sensitive)
3rd Alternative
\>
\> matches the character > with index 6210 (3E16 or 768) literally (case sensitive)
= matches the character = with index 6110 (3D16 or 758) literally (case sensitive)
3rd Alternative
\<\=
\< matches the character < with index 6010 (3C16 or 748) literally (case sensitive)
\= matches the character = with index 6110 (3D16 or 758) literally (case sensitive)
4th Alternative
\>\=
\> matches the character > with index 6210 (3E16 or 768) literally (case sensitive)
\= matches the character = with index 6110 (3D16 or 758) literally (case sensitive)
4th Capturing Group
(.+)
.
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

Substitution

Processing...