Unix Command List for Beginners
Hello and welcome to Beare's Unix Command List for Beginners. This page describes basic and useful Unix commands in layman's terms.
ls
Lists the contents of a file.
pwd
Stands for Print Written Directory. Prints the name of the working directory eg /home/folder
whoami
Prints the username of the user currently logged on.
who
Displays a list of users who are currently logged on.
cd
Stands for Change Directory. Used to change the current working directory. eg cd /home/folder1
cat
Displays the contents of a file eg cat test.txt
touch
Used to create a new empty file eg touch newfilecp
Copies a directory or file.
df
Abbreviation for Disk Free. Shows the amount of used/free space for filesystems. Useful command to see how much space is left on your hard drive.
free
Displays memory usage - total, free, used.
uptime
Displays how long the server has been on for. Also displays the number of users who logged on and the average CPU load for the past 1, 5 and 15 min intervals.
ifconfig
Used to setup a network interface card. Allows you to configure the ip address, netmask and default gateway. The command uses the following convention:ifconfig (interface) (ip address) netmask (netmask ip) up/down
For example, the following command applies an ip address and netmask to the ethernet 0 interface and turns it on (up): ifconfig etho0 192.168.1.5 netmask 255.255.255.0 up
banner
Outputs a larger version of whatever you type eg banner hello world!
wall
Displays a message to all logged on users. Useful for root sending a message to all users advising of a system shutdown. Type wall and press enter. Now type your message followed by enter and ctrl-d.
echo
Outputs text to the screen eg echo Hello world!
uname
Stands for Unix Name. Displays details such as the name and version of your computer and Operating System. Try running uname -a for an extended output.
top
Produces a list of top-resource consuming processes ordered by CPU usage. Also displays current CPU utilisation.
htop
Similar to top expect it displays a full list of process running, not just the top-resource consuming processes. It's also in colour.
ps
Short for Process Status. Similar to top, displays all running processes.
kill
Used to end a process. Eg to close a process with an ID of 1234 type kill 1234.
pkill
Can kill a process based on name rather than PID, eg pkill firefox.