Condition statement in perl

#!/usr/bin/perl
$output1 = "/home/log.txt"
$output2 = "/home/grep.txt"

#Statement1 creates an output file called log.txt.

#Statement2 greps a line from log.txt and store the result in grep.txt

I want to create a condition where if the file grep.txt is empty repeat process.

Thanks.

there is no ; semicolon in second line...

and both the statement does just assignment to a variable, nothing more.