Always use 3-argument open
Appending to files
Command line counter with plain text file back-end
Count the frequency of words in text using Perl
Don't Open Files in the old way
How to check if a string is all upper case (lower case) characters?
How to improve my Perl program?
How to merge one text file to the end of another text file?
How to replace a string in a file with Perl
How to split a text file line by line in Perl
How to write to the beginning of a file?
Old style open - video
Open and read from text files
Open file - video
Open file all - video
Open file to read and write in Perl, oh and lock it too
Open file with error handling - video
Open or die - video
Reading and writing binary files in Perl