Regular Expressions 101

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/
^(-) (.{1,})\n(.+)
/
gmsU
^ asserts position at start of a line
1st Capturing Group
(-)
- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
matches the character with index 3210 (2016 or 408) literally (case sensitive)
2nd Capturing Group
(.{1,})
.
matches any character
{1,} matches the previous token between one and unlimited times, as few times as possible, expanding as needed (lazy)
\n matches a line-feed (newline) character (ASCII 10)
3rd Capturing Group
(.+)
.
matches any character
+ matches the previous token between one and unlimited times, as few times as possible, expanding as needed (lazy)
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)
s modifier: single line. Dot matches newline characters
U modifier: Ungreedy. The match becomes lazy by default. Now a ? following a quantifier makes it greedy
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
gmsU

Test String