How to replace all lines in multiline string starting with #

str.replace(/^#([^\n]*)\n$/gm, '<h1>$1</h1>')

multiline string

# headline
some text

# new headline
some more text

result string

<h1>headline</h1>
some text

<h1>new headline</h1>
some more text

How to replace all lines in multiline string starting with #

str.replace(/^#([^\n]*)\n$/gm, '<h1>$1</h1>')

multiline string

# headline
some text

# new headline
some more text

result string

<h1>headline</h1>
some text

<h1>new headline</h1>
some more text

• javascript
• regex

• So the goal is to match everything from any start-of-line + hash to the closest end-of-line? Why does that feel trivial to me? – John Dvorak Commented Nov 18, 2013 at 12:31

3 Answers 3

try this regexp /^#(.*)$/mg like this

str.replace(/^#(.*)$/mg,"<h1>$1</h1")

If your line breaks are \n, then this will work:

#(.*?)(\n|$)

Javascript:

str.replace(/#(.*?)(\n|$)/g,"<h1>$1</h1>")

^#\s(\w+)$ Will match any line beginning with a #, followed by a single whitespace character and then followed by at least 1 word character (A-Z, 0-9 and underscores). It then stores a match group of the headline text.

You should be able to call this match group with \1.