File Opening, Input, Output and Sorting

File Handles

open (FILE_HANDLE, “file.name”);

Open for reading:

open (SONGS, “song_list.txt”);

open (SONGS, “song_list.txt”) or die “Can’t open that file! Error is $!”;

 

Retrieve lines using < > :

open (SONGS, “song_list.txt”) or die “Can’t open that file!”;
for $line (<SONGS>) {
print $line;
}

 

Open for overwriting:

open (SONGS, “>song_list.txt”) or die “Can’t open that file!”;
# Be aware that any original contents are now gone!

 

Open for appending:

open (SONGS, “>>song_list.txt”) or die “Can’t open that file!”;
# The original contents are preserved, just appended onto.

 

Writing to the file:

open (SONGS, “>song_list.txt”) or die “Can’t open that file!”;
print SONGS “Stairway to Heaven\n”;
# Everything else is gone

 

Appending to the file:

open (SONGS, “>>song_list.txt”) or die “Can’t open that file!”;
print SONGS “Copacabana\n”;

 

File Operations

Steve Litt’s PERLs of Wisdom: PERL File Input, Output and Sorting

(also see the root of this “tips” area, Steve Litt’s Perls of Wisdom)

Formatting and Printing: sprintf()

Perl File Handling: open, read, write and close files at Perlfect Solutions

-note the use of the returned error code (which isn’t always an error), $!

-and the “current line” special variable $_

-and the operator <FILE>

Perl tutorial at tizag.com

The Kinder, Gentler File Opening Tutorial at Perldoc.perl.org

File Handling at DevelopingWebs.net