chmod

chmod mode, filelist

• Changes the permissions of a list of files. The first argument must be the permissions mode given in its octal number representation. The function returns the number of files successfully changed. For example:
  
  

  $cnt = chmod 0755, 'file1', 'file2';
  

  
  
  will set $cnt to 0, 1, or 2, depending on how many files got changed (in the sense that the operation succeeded, not in the sense that the bits were different afterward).