Binary package “procps” in ubuntu lucid

/proc file system utilities

 These are utilities to browse the /proc filesystem, which is not a real file
 system but a way for the kernel to provide information about the status of
 entries in its process table. (e.g. running, stopped or "zombie")
 Both command line and full screen utilities are provided. Ncurses is needed
 for the full screen utilities. More information can be found at procps
 This package includes the following utilities: top, uptime, tload,
 free, vmstat, watch, skill, pmap, pgrep, slabtop and pwdx.