ATTRIB

The ATTRIB command can be used to make files hidden, read-only, system, and archive. To change a file that is visible to a hidden file, you would enter ATTRIB +H and the filename with it's extension at the C:\ prompt in the directory that contains the file. Such as C:\ATTRIB +H visible.doc. To make a file read-only prevents any unwanted changes from occurring. At the C:\ prompt you would enter C:\ATTRIB +R readme.doc. This command will deny access to anyone trying to make changes or delete the file. To remove the read-only attribute from the file, enter C:\ATTRIB -R readme.doc.
Some of the switches associated with the ATTRIB command are:
+H to hide a file in a directory
-H to view a previously hidden file
+A to set a file flag so it can be archived during a backup or XCOPY
-A to remove the archive flag
+S to set a file as a system command
-S to remove the flag for a system command file
+R to set the file up for read-only
-R to remove the read-only attribute

You can also use multiple switches with the ATTRIB command. For instance, if you wanted to set a file up as a system file that is hidden. You would enter the ATTRIB command: C:\ATTRIB +S +H helloworld.exe. To reverse these settings you would substitute the +S +H with the -S -H switches.