Useful Linux Commands - Part 1

The following are a list of commonly used Linux Administration Commands.

Linux System Information Commands

Linux Command Description
w Display Who is online and their processes
who Show who is logged on
whoami Display effective userid
id Display user and groups
groups Display the groups a user is in
finger user Display user information
uname -a Display Kernel Information
man command Display man pages for specified command
man -k keyword Search man pages for referenced keyword
apropos keyword Search man pages names and descriptions for specified keyword
df -h Display Disk Usage in MB and GB
du Display an estimate of file space usage
free Display Memory and Swap Information
dmesg Display kernel ring buffer. Often used as - dmesg | grep -i "search-string"
uptime Displays system uptime since boot and system Load averages
runlevel Displays previous and current runlevel of system
hostname Displays hostname of system
chkconfig --list Displays System services run levels
env Display current environment
lsusb List USB devices
lspci List all PCI devices
lshw List hardware (run as root user)
lshal List items in HAL Database
tty Print the name of the terminal attached to Standard Input