Anyone tell me about $fh. f mean file and h mean?

Answer 1

$fh means file handler like STDIN or STDOUT

Answer 2

what comes from fopen() is normally assigned to $fn. Now you'll use this file handler to operate on the file. And don't forget to close it afterwards.

Answer 3

$fh does not mean anything. Its a variable used to handle fopen() function. you can use something like $myFile or anything instead of $fh.