regex get first match code example

Example 1: regex match to first instance

/[^;]*/

# matches every character before the first ;

Example 2: regex find first instace

adding ".*?" To a answer makes it non greedy

running <h2)*?>

on

<h2 style="text-align: center;">heading</h2>

will return <h2 style="text-align: center;">

Example 3: regex first in line

Just use "^" to specify matching a pattern at the beginning of each line.
Example with grep:
grep "^pattern" file.txt