DaTe Gulis

Useful tools and links to get you started as a DaTe member.

Intro to Linux

Linux is a UNIX-like operating system. On this page you find the some useful information and the most common commands used in the Linux environment.

Learn to love it, you won’t be disappointed.

If you want more information about a command, the usual way is to use the --help argument or the man <command> command.

Table of Contents

Terminal commands

Network commands


Basic information

For windows people - Directory == Folder

Terminal (the command line cmd on Windows never was)

Here the user is located in their home directory ~ :


And here the user would be in current_directory:


Absolute path, starts from root directory:


Relative path, starts from current directory:


Basic commands

sudo - “superuser do”

Allows users to run programs with the security privileges of another user, by default the superuser. Use this command in front of any command if you get access denied, or don’t, you may potentially destroy something.

username@linux:~$ sudo <command>

man - show manual for command

Almost every linux command comes with a manual. Use man to access it.

If you would like to know more about the command ls, you would type:

username@linux:~/$ man ls

To exit the manual, press q.

top - monitor processes and system resources (task manager)

start process by simply typing

username@linux:~/$ top

top will show all running processes. TODO: update list (DONT USE THIS!!!)

Mem: 60964K used, 1532K free, 0K shrd, 9044K buff, 36972K cached
CPU:   8% usr  57% sys   0% nice   4% idle  29% io   0% irq   0% softirq
Load average: 1.88 0.88 0.39
  200   198 root     S     214m 350%  44% ./tuska_interface
   19     2 root     DW<      0   0%  14% [mmcqd]
  249   233 root     R     3144   5%   0% top
   12     2 root     SW<      0   0%   0% [kswapd0]
  203     1 root     S     3144   5%   0% telnetd -p 23 -b
  233   203 root     S     3144   5%   0% -sh
  198     1 root     S     3144   5%   0% /bin/sh /etc/init.d/rcS
    1     0 root     S     3140   5%   0% init
   36     1 root     S <   1592   3%   0% /sbin/udevd --daemon
   17     2 root     SW<      0   0%   0% [ubi_bgt0d]
    9     2 root     SW<      0   0%   0% [kmmcd]
    2     0 root     SW<      0   0%   0% [kthreadd]
    3     2 root     SW<      0   0%   0% [ksoftirqd/0]
    4     2 root     SW<      0   0%   0% [events/0]
    5     2 root     SW<      0   0%   0% [khelper]
    6     2 root     SW<      0   0%   0% [kblockd/0]
    7     2 root     SW<      0   0%   0% [ksuspend_usbd]
    8     2 root     SW<      0   0%   0% [khubd]
   10     2 root     SW       0   0%   0% [pdflush]
   11     2 root     SW       0   0%   0% [pdflush]
   13     2 root     SW<      0   0%   0% [aio/0]
   14     2 root     SW<      0   0%   0% [nfsiod]
   15     2 root     SW<      0   0%   0% [scsi_tgtd/0]
   16     2 root     SW<      0   0%   0% [mtdblockd]
   18     2 root     SW<      0   0%   0% [rpciod/0]
  191     2 root     SW<      0   0%   0% [ubi_bgt1d]
  195     2 root     SW<      0   0%   0% [ubifs_bgt1_0]

For a list of commands you can use inside top, press the h key while the program is running.

As an example, you kan press k to kill a process. Just enter the process ID (PID) after pressing k, or press enter to kill the topmost process.

To terminate a process outside top, use kill PID, where PID is the process you want dead.

pwd - print working directory

Self explanatory, prints where you are in directory hierarchy.

username@linux:~/$ pwd

Prints the absolute path for the current working directory, AKA where you currently are.

ls - list files in directory

Lists all files in current or specified directory.

List all files in the current directory, here Downloads:

username@linux:~/Downloads$ ls

List all files inside the Music/classic directory:

username@linux:~$ ls Music/classic

cd - change directory

Move inside a directory:

username@linux:~$ cd <directory_path>

To move to the parent directory:

username@linux:~$ cd ..

. refers to current directory, while .. refers to the parent.

rm - remove file/directory


username@linux:~$ rm

Remove a directory:

username@linux:~$ rm -r awesomeDirectory

The -f is used to remove forcefully:

username@linux:~$ rm -rf awesomeDirectory

cp - copy file/directory

Copy a file to a target. If the target is a directory, the filename will remain unchanged:

username@linux:~$ cp sourcefile tagetdirectroy

This would also rename the new file from a.txt to b.txt:

username@linux:~$ cp a.txt tagetdirectroy/b.txt

Use -r to copy a directory and its contents:

username@linux:~$ cp -r sourcedirectory targetdirectory

mv - move file/directory

Use this to move a file/directory to its destination:

username@linux:~$ mv source taget

Move multiple files into a directory:

username@linux:~$ mv file1.txt file.2.txt file3.txt directory

Move all files with .py extension into a directory

username@linux:~$ mv *.py directory

Rename a.txt to b.txt by moving inside same directory:

username@linux:~$ mv a.txt b.txt

mv can, like cp, also move directories.

mkdir - create directory

Used to create directories.

username@linux:~$ mkdir directoryname

Network commands

ping - ping a server/website

Use this to ping a website. useful if you want to test your network connection or if a server is up.

username@linux:$ ping

ssh - remote access computer or server

Use this to remote access a server, e.g. tuxedo.

username@linux:$ ssh user@server

To connect using a different port than the default 22, use the -p flag:

username@linux:$ ssh user@server -p 1234

The following will connect to tuxedo, to your account:

username@linux:$ ssh

More about tuxedo: tuxedo-wiki

telnet - Talk to “hosts” at the given port number

By default, the telnet port is port 23. Few other famous ports are:
7 – echo port,
25 – SMTP, use to send mail
79 – Finger, provides information on other users of the network

username@linux:$ telnet host <port>

ifconfig - network interface configuration/info

Shows your network interfaces and displays information about them. Similar to ipconfig on Windows.

Show all network interfaces:

username@linux:$ ifconfig

Show a specific interface:

username@linux:$ ifconfig eth0

This command is being slownly replaced py ip. Try to do man ip to read more about it if it is available on your system.

iwconfig - like ifconfig but for wireless interfaces

Almost the same as ifconfig but only displays wireless interfaces.

username@linux:$ iwconfig

whois - Who dis?

domain lookup

username@linux:$ whois

TODO: improve description

nslookup - translate IP address to name

Makes queries to the DNS server to translate IP to a name, or vice versa. eg. nslookup will gives you the IP of

traceroute - tracing route of IP address

Useful for tracing the route of IP packets. The packet causes messages to be sent back from all gateways in between the source and destination by increasing the number of hopes by 1 each time.

Text editors

This needs its own section.

Different text editors:

10 best Text editors for linux and programming 2017


sudo “superuser do”. Use this command infront of any command if you get access denied.
man Manual for each command.
top Rerminal task manager
pwd Print working directory
ls Lists all files in current or specified directory.
cd Move between directories
rm Remove a file
rm -r Remove a directory
cp Copy a file
cp -r Copy a directory
mv Move a file
mkdir Create new directory
ping Ping server/website to test network connection.
ssh Remote access computer or server.
ifconfig Network interface configuration and info.
iwconfig Network interface configuration and info for wireless connections only.
whois Doman lookup
nslookup Translate IP address to name
traceroute Tracing route of IP address