Skip to main content

Basic Linux Commands for Beginners

Using a Linux machine using a shell Prompt is always a challenge these days. Many of us feel it is tougher to use Linux because of its Conventional Shell prompt, but the GUIs are so sophisticated when compared with Other Operating systems like windows, etc.

But still as a developer, one has to be good at Linux both in the GUI and as well as in Shell. For novice users and beginners, the following commands will make understand the importance of Linux and their commands.

Basic Commands

Commands usage Explanation
ls ls to list the files and folders
ls –l ls –l to list the files and folders in long format
chmod chmod 777 filename to change the mode of a file
pwd pwd display the present working directory
passwd passwd Changing the password of the current user
echo echo “hello” display the string hello
  echo $PATH Display the PATH Variable stored
  echo $HOME display the Home folder of the current user
  echo $SHELL displays the type of shell used /bin/bash
tar tar xf filename.tar to decompress the tar file and extract the folders
  tar xvf filename.tar to decompress the tar file and extract the folders with verbose mode
  tar zxvf filename.tar.gz to decompress from gzip and the extract the tar created.
gzip gzip –d filename.tar.gz
gzip –d filename.gz
to decompress the gzip file
bzip2 bzip2 –d filename.tar.bz2
bzip2 –d filename.bz2
to decompress the bzip2 file
rm rm name remove a file or directory called name (the directory should be empty to be deleted)
  rm –rf name

Kill off an entire directory and all it’s
includes files and subdirectories

cp cp filename /home/hello copy the file called filename to the folder /home/hello
mv mv filename /home/hello move the file called filename to the directory /home/hello
cat cat filename display the file called filename
su su login to superuser from current login (you should know the super user password)
exit exit exit out of the shell window or Stop being superuser and revert to normal user
dmesg dmesg display the boot time messages
ls ls list current processes
kill kill 123 kill a specific process with ID 123
ifconfig ifconfig

List ip addresses for all devices on
the machine

rpm rpm –ivh filename.rpm Install the rpm package called name
  rpm –Uvh filename.rpm

Upgrade the rpm package called

  rpm –e package

Delete the rpm package called

  rpm –l package

List the files in the package called

./configure ./configure

Execute the script preparing the
installed files for compiling

find find / –name fname

Starting with the root directory, look
for the file called fname

  find / -name ”*fname*”

Starting with the root directory, look
for the file containing the string fname


File Permissions


If the command ls -l is given, a long list of file names is displayed. The first column in this list details the permissions  applying to the file. If a permission is missing for a owner,
group of other, it is represented by - eg.

Read = 4
Write = 2
Execute = 1
File permissions are altered by giving the chmod command and the appropriate octal code for each user type. eg chmod 7 6 4 filename will make the file called filename R+W+X for the owner, R+W for the group and R for others.

chmod 7 5 5 Full permission for the owner, read and execute access for the group and others.
chmod +x filename Make the file called filename executable to all users.


Popular posts from this blog

Installation of NS2 (ns-2.35) in Ubuntu 20.04

Installation of NS2 (ns-2.35) in Ubuntu 20.04 LTS Step 1: Install the basic libraries like      $] sudo apt install build-essential autoconf automake libxmu-dev Step 2: install gcc-4.8 and g++-4.8 open the file using sudo mode $] sudo nano /etc/apt/sources.list Include the following line deb bionic main universe $] sudo apt update $] sudo apt install gcc-4.8 g++-4.8 Step 3:  Unzip the ns2 packages to home folder $] tar zxvf ns-allinone-2.35.tar.gz $] cd ns-allinone-2.35/ns-2.35 Modify the following make files. ~ns-2.35/ Change @CC@ to gcc-4.8 change @CXX@ to g++-4.8 ~nam-1.15/ ~xgraph-12.2/ ~otcl-1.14/ Change in all places  @CC@ to gcc-4.8 @CPP@ or @CXX@ to g++-4.8 open the file: ~ns-2.35/linkstate/ls.h Change at the Line no 137  void eraseAll() { erase(baseMap::begin(), baseMap::end()); } to This void eraseAll() { this->erase(baseMap::begin(), baseMap::end()); } All changes made Step 4: Open a new termi

Installing ns-3.34 in Ubuntu 20.04

This post shows how to install ns 3.34 in Ubuntu 20.04 LTS Prerequisites: Fresh installation of Ubuntu Version 20.04 LTS  ns3.34 can be downloaded from here Follow the video link for complete step by step instructions on the installation.  This version fixes the compilation issues of (bug in ns3.33)  Issue the following commands after opening a terminal  $ sudo apt update $ sudo apt install g++ python3 python3-dev python-dev pkg-config sqlite3 python3-setuptools git qt5-default gir1.2-goocanvas-2.0 python3-gi python3-gi-cairo python3-pygraphviz gir1.2-gtk-3.0 ipython3 openmpi-bin openmpi-common openmpi-doc libopenmpi-dev autoconf cvs bzr unrar openmpi-bin openmpi-common openmpi-doc libopenmpi-dev tcpdump wireshark libxml2 libxml2-dev Unzip or untar the ns-allinone-3.34.tar.bz2 in the home folder (in my case its /home/pradeepkumar) $ cd ns-allinone-3.34/ $ ./ --enable-examples --enable-tests  Once the installation is completed, you may get an output show

Installation of ns3 in Windows 10 and Windows 11 OS using WSL (Windows Subsystem for Linux)

This post shows how to install ns-3.33 in Windows 10 through WSL (Windows Subsystem for Linux) This posts works for Windows 11 also (I have tested it on a Windows 11 ISO and it works the Same way as mentioned in the following post.) This post will work for ns-3.3x version. Prerequisites : Install Windows Subsystem for Linux with GUI: Please refer the following video  System Information: OS used: Windows 10 and WSL (Ubuntu 20.04) GUI: XServer for Windows NS3 Version: ns-3.33 See the following complete video on how to install ns3 in Windows 10 Step 0 : Open XLaunch Step 1 :  Open WSL using PowerShell and open it as Administrator Command:/  wsl $ xfce4-session The GUI of Ubuntu Opens within Windows 10 OS. Step 2 : Download ns3 from website through Mozilla Firefox browser Step 3: Open a Terminal  $ sudo apt update $ sudo apt install build-essential autoconf automake libxmu-dev python3-pygraphviz cvs mercurial bzr git cmake p7zip-full python3-matplotlib python-tk python3-dev qt5-q