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Getting a handle on files
- File handles are variables, but they don't require a
special symbol (like $)
- File handles are created + assigned by opening a file
- Opened files should be specified for read, write+truncate,
write+append, or read+write
- man perlfunc has an extensive reference section
on the open function. man perlopentut for a
detailed tutorial on opening files
- There are many options for opening and reading/writing files.
These include:
- Accessing fixed-length records or database (see tie)
- Reading + writing from Unix pipes
- Specifying binary files, Unicode files, or other "types"
- Treating STDIN and STDOUT as files
- Basic syntax example:
#!/usr/bin/perl -w
use strict;
my $infile="file1.txt"; # input filename
# Open; assign filehandle; exit on error:
open (IN, "<$infile") or die "Open of $infile failed: $!";
# Loop: read lines from the file
while (<IN>) {
print $_; # Each input line is assigned to $_
}
# Clean up and exit:
close(IN);
exit;
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