if you pass 3 separate arguments to open(), then your program will not compile with earlier perl interpreters!

Perl 5.6, which introduced the 3-argument open, was released more than 18 years ago. AFAIK people being stuck on a Perl <5.6 should be pretty rare nowadays.

The two-argument form of open will invoke external programs if the first or last character of the filename is a pipe (|). If the filename is user-supplied, this is a security risk! Also, the two-argument form doesn't let you specify I/O layers such as ':encoding(UTF-8)'. That's why the three-argument form is recommended nowadays.

make sure that my code will be backwards compatible

Your code won't run on a Perl <5.6 because warnings wasn't introduced until 5.6.

Notice that you do not need to use a variable for file handle. You can use numbers.

What advantage does this have? (Especially to a beginner?)

I am not sure if Perl automatically closes the open file handle when we call die()

It does.

In reply to Re^2: First attempt at bringing in file for input/output by haukex
in thread First attempt at bringing in file for input/output by catfish1116

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