UPX

UPX (Ultimate Packer for eXecutables) is a popular executable compression application.

UPX supports several different executable formats, including Microsoft Windows and MS-DOS. UPX-compressed executables can often be identified as such, for example by the file command.

UPX traditionally uses a data compression algorithm named UCL, though other algorithms may also be available.

Links

 * UPX website
 * UPX