Overview
- Introduction
- Check if file exists
- Get file size
- Change file permissions
- Deleting Files
- Opening and closing files
- Read file contents
- Write to a file
- Conclusion
Introduction
Perl is commonly used for sysadmin tasks which frequently involves managing files. These examples demonstrate how to read, write, and append files with Perl.
Check if file exists
if ( -e "test.txt") {
print "File exists.";
}Get file size
my $fileSizeInBytes = -s 'test.txt';Change file permissions
chmod(0755, $filePath);Deleting Files
unlink($filePath);Opening and closing files
$file = '/home/NanoDano/test.txt';
# Pick only one of these
open(INFO, $file); # Open for input
open(INFO, "<$file"); # Another way for input
open(INFO, ">$file"); # Open for output
open(INFO, ">>$file"); # Open for appending
# Close when finished
close(INFO);Read file contents
# Store all the lines of the file in to an array
@lines = <INFO>; Write to a file
You can provide the print function a file handle to specify where to write the output. It defaults to standard output, but we can specify the file handler of our open file.
print INFO "This line goes to the file.\n";Conclusion
With this knowledge, you should be able to perform basic file manipulation tasks.