perl function chmod

In Perl, the chmod function is used to change the permissions of a file or directory. It takes two arguments: the new mode as an integer and the list of files to modify. The mode is a combination of permissions specified in octal form.

Here's an example that demonstrates the use of the chmod function:

use strict;
use warnings;

# create a test file
my $filename = 'test.txt';
open(my $fh, '>', $filename) or die "Cannot open file: $!";
close($fh);

# set the file permissions to 0644 (rw-r--r--)
chmod(0644, $filename);

# get the current file permissions
my $mode = (stat($filename))[2] & 07777;
printf "Current file mode: %04o\n", $mode;

# set the file permissions to 0755 (rwxr-xr-x)
chmod(0755, $filename);

# get the updated file permissions
$mode = (stat($filename))[2] & 07777;
printf "Updated file mode: %04o\n", $mode;

# remove the test file
unlink $filename;

In the above example, we first create a test file using the open function and then close it. We then use the chmod function to set the file permissions to 0644 (readable and writable by the owner, readable by everyone else). We use the stat function to get the current file permissions, which we print to the screen using the printf function.

We then use the chmod function again to set the file permissions to 0755 (readable, writable, and executable by the owner, readable and executable by everyone else). We again use the stat function to get the updated file permissions, which we print to the screen using the printf function.

Finally, we remove the test file using the unlink function.

When run, the above example will output something like the following:

Current file mode: 0644
Updated file mode: 0755

This indicates that the file permissions were successfully changed from 0644 to 0755.