Which Mac OS X versions support lsof command? I want to know which Mac OS X versions support the lsof command. Does Mac OS X 10.5 support it?
lsof has been available since OS X 10.5. From the manual page :

   Lsof  revision 4.87 lists on its standard output file information about
   files opened by processes for the following UNIX dialects:

        Apple Darwin 9 and Mac OS X 10.[567]