for Solaris 10 05/08 or higher, the 0508 package must be used. If the 0508 version does not run properly, try the 11/06 version.) lsof lists information about files that are open by the processes running on a UNIX system. This package contains both a 32 and 64-bit version of lsof, but you only need to type lsof to run the program. - installs in /usr/local. lsof is typically run as root.