meaning of `$/i` in regular expressions

Question

What does the $/i mean in the following php code?

preg_match ('/^[A-Z \'.-]{2,20}$/i')

Answer 1

/ denotes the end of the pattern. The i is a modifier that makes the pattern case-insensitive, and the $ anchor matches the end of the string.

Answer 2

the $ is an anchor -- it means the end of the string should be there. the / is the end delimiter for the regular expression. The i means that the regular expressions should be case-insensitive (notice that [A-Z \'.-] only matches A-Z -- the i means it doesn't have to look for a-z as well).