System Information Commands

df

The df command displays filesystem disk space usage for all partitions (df stands simply for "disk free").

df -h

will give information using megabytes (M) and gigabytes (G) instead of blocks (-h means "human-readable").

free

The free command displays the amount of free and used memory in the system.

free -m

will give the information using megabytes, which is probably most useful for current computers.

top

The top command displays information on your GNU/Linux system, running processes and system resources, including CPU, RAM & swap usage and total number of tasks being run. To exit top, press q.

uname

The uname command with the -a option, prints all system information, including machine name, kernel name & version, and a few other details. Most useful for checking which kernel you're using.

lsb_release

The lsb_release command with the -a option prints version information for the Linux release you're running. For example, typing:

lsb_release -a

will give you:

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 7.10
Release:        7.10
Codename:       gutsy

ifconfig

The ifconfig command reports on your system's network interfaces (ifconfig stand for "interface config").

ifconfig is commonly used to find out the IP address of your computer on its network or the internet. To find this information easily type:

ifconfig | grep "inet addr"