1. The /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. From Debian 3.0r0 APT

2. The procps package contains a set of system utilities that provide system information. Procps includes ps, free, skill, snice, tload,top, uptime, vmstat, w, and watch. The ps command displays a snapshot of running processes. The top command provides a repetitive update of the statuses of running processes. The free command displays the amounts of free and used memory on your system. The skill command sends a terminate command (or another specified signal) to a specifiedset of processes. The snice command is used to change the scheduling priority of specified processes. The tload command prints a graph of the current system load average to a specified tty. The uptime command displays the current time, how long the system has been running, how many users are logged on, and system load averages for the past one, five, and fifteen minutes. The w command displays a list of the users who are currently logged on and what they are running. The watch program watches a running program. The vmstat command displays virtual memory statistics about processes, memory, paging, block I/O, traps,and CPU activity. From Redhat 8.0 RPM