
The df command displays filesystem disk space usage for all partitions. (df stands for “disk free”).
df -h
will give information using megabytes (M) and gigabytes (G) instead of blocks (-h means “human readable”).
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 the most useful for current computers.
The top command displays information on the Linux™ system - processes that are running, system resources including CPU, RAM & swap usage, and the total number of tasks being run. To exit top, press q.
The uname command with the -a option displays all system information, including machine name, kernel name & version, and other details. This command is useful for checking which kernel is in use. (uname is short for “unix name”).
The lsb_release with the -a option prints version information for the Linux™ release in use. For example, typing:
lsb_release -a
will display:
No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 12.04 Release: 12.04 Codename: precise