Tuesday, May 17, 2011

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
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