Regular Expressions Anchor Characters: Caret (^) Start of Line
Example
When multi-line (?m) modifier is turned off, ^ matches only the input string's beginning:
For the regex
^He
The following input strings match:
Hedgehog\nFirst line\nLast lineHelp me, pleaseHe
And the following input strings do not match:
First line\nHedgehog\nLast lineIHedgehogHedgehog(due to white-spaces)
When multi-line (?m) modifier is turned on, ^ matches every line's beginning:
^He
The above would match any input string that contains a line beginning with He.
Considering \n as the new line character, the following lines match:
HelloFirst line\nHedgehog\nLast line(second line only)My\nText\nIs\nHere(last line only)
And the following input strings do not match:
Camden Hells BreweryHelmet(due to white-spaces)
Matching empty lines using ^
Another typical use case for caret is matching empty lines (or an empty string if the multi-line modifier is turned off).
In order to match an empty line (multi-line on), a caret is used next to a $ which is another anchor character representing the position at the end of line (Anchor Characters: Dollar ($) ). Therefore, the following regular expression will match an empty line:
^$
