### System Utilities ###

 1. Process listing
 2. Free/available memory
 3. Disk utilization

1. ps - process status/listing
 a. ps -ef or ps -aux
2. top - combines, ps, uptime, free and updates regulary
3. uptime - returns useful system utilization information:
 a. current time
 b. uptime - days, hours and minutes
 c. connected users
 d. load averaged - 1,5,15 minute values
4. free - returns memory utilization
 a. RAM
 b. SWAP
 free -m - for human readable format
5. df - returns disk partition/mount point information
 a. df - returns info. using kilobytes
 b. df -h - returns info. using megabytes/human readable (gigs/teray/etc.)
6. vmstat - reports on: processes, memory, paging, block I/O, traps, CPU activity
 a. vmstat
 b. vmstat -p /dev/hda1 - returns partitions stats for /dev/hda1 (/boot)
7. gnome-system-monitor - GUI, combining most system utilities
8. ls -ltr /proc
 a. cat /proc/cpuinfo
9. kill PID - kills the process with a given PID
10. runlevel - returns runlevel information using 2 fields:
 a. represents previous runlevel
 b. represents current runlevel