To change the Unix file permissons of a file:

Use the [file->chmod] tag. The following example changes the Unix file system permissions of a file to -rwxrwxr-x (read, write, and execute permissions for the file owner, read, write, and execute permissions for the file group, and read and execute permissions for all other system users).

Code

local(f = file('/path/to/file.txt'))
#f->chmod('0775') // using octal notation
#f->chmod(509) // using decimal notation