perl handle and common variable

anaconda_wly has asked for the wisdom of the Perl Monks concerning the following question:

below is the way creating a file a write. open report_handler, ">", "report.txt"; Can I change the file handle "report_handler" to a variable starting with $?

my $report_handler;
open $report_handler, ">", "report.txt";
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I tried and seems OK, so why we need the file handle?

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Re: perl handle and common variable by aitap (Curate) on Apr 08, 2013 at 07:03 UTC
If you mean the `report_handler` bareword by "file handle", that's because in the past (before version 5.6) Perl didn't have ability to work with lexical filehandles, and bareword filehandles were used instead. Read Typeglobs and Filehandles and https://www.socialtext.net/perl5/bareword_uppercase_filehandles for more information on bareword filehandles. They are also easier to understand by Perl beginners. _{Edit: lexical fh's introduced in 5.6}	[reply] [d/l]
Re: perl handle and common variable by dsheroh (Monsignor) on Apr 08, 2013 at 09:48 UTC
Just to clarify some terminology that it appears you may have misunderstood: At the end of your second bit of posted code, `$report_handler` is a file handle. A "file handle" is the operating-system level resource used by programs to interact with files (and other file-like things, like pipes, stdin, stdout, etc.). The difference you've discovered is the difference between a bareword (or typeglob) file handle (`report_handler`) and a lexical file handle (`$report_handler`). Bareword file handles mostly exist for the sake of backwards compatibility these days. Any new code should use lexical file handles instead.	[reply] [d/l] [select]
Re: perl handle and common variable by Anonymous Monk on Apr 08, 2013 at 06:00 UTC
I tried and seems OK, so why we need the file handle? Because you didn't read the documentation for open or perlintro?	[reply]
Re: perl handle and common variable by Rahul6990 (Beadle) on Apr 08, 2013 at 06:10 UTC
File handle is required to perform read and write operation on the underlying file. For accessing the file content you have to go through the file handle. Example: $file = '/etc/passwd'; # Name the file open(INFO, $file); # Open the file @lines = <INFO>; # Read it into an array close(INFO); # Close the file print @lines; # Print the array	[reply]