Monitoring various aspects of your system

Author: John M. Gabriele | back to index

Monitoring various aspects of your system

• System Monitoring
• General
• Who has which files open?
• CPU
• Memory
• CPU and processes
• disk info
• Network traffic
• Network settings
• Users
• Log files

---

System Monitoring

Many of the following commands can be run by the watch command, which runs a command for you every 2 seconds and shows the ouput full-screen.

More general info here:

• http://www.tldp.org/LDP/sag/html/system-monitoring.html
• http://www.karakas-online.de/gnu-linux-tools-summary/
• http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/admin-primer/s1-resource-rhlspec.html

General

The /proc directory is chock full of system information. Some utilities will process that info a bit to make it more digestible.

• lsmod
• vmstat
• uname -a
• cat /etc/debian_version
• cat /proc/version

Who has which files open?

• fuser <filename> [...] -- show processes using specified file. Use -u to show the actual username.
• lsof <file_name> -- see the end of its man page for examples.

CPU

• cat /proc/cpuinfo

Memory

• free -- Use with -m to see it in MB

CPU and processes

• top -- Show the table of processes, updated live
• ps -el -- List all processes ("every" one of them) in long format.
• ps -eo pid,tt,user,fname,args,%cpu --sort %cpu -- Like before, but sort by cpu usage. Nice.
• pstree

disk info

• fdisk -l
• cat /etc/mtab
• df -h -- Shows how disk space is being used on all mounted partitions.
• du -hs [directory|file] ... -- Shows how much space a given directory or file (or many of them) are taking up.

Network traffic

• mtr <url|ip_address> -- Matt's traceroute.
• ping <url|ip_address>
• traceroute <url|ip_address> -- example: tcpdump -i eth0 src or dst host 10.0.0.3

Network settings

• route
• ifconfig -a
• netstat -n
• lsof -i :<port_num>

Users

• last -- listing of last logged-in users

Log files

• tail -f /var/log/messages -- Tail this file, as well as others in /var/log.