Linux basic Commands

 

 
 

Introduction

 
The Linux command line is a text interface to your computer. Often referred to as the terminal. It can look confusing and complex to use. In this post basic commands will be used to perform certain tasks.

 
Creating a new user : sudo adduser <username>
                            Example: sudo adduser hsenid
 
 
Reset password for the newly created user : sudo passw <username>
                            Example : sudo passwd hsenid
 
 
Create a directory called my_group in home directory and give permissions to user and group
 
Make directory : mkdir my_group
Give permission : chmod u+o my_group


Create a directory called my_user in home directory and give permissions to user only
 
Make directory : mkdir my_user
Provide permission : chmod u+rwx my_user


Check how many network interfaces your computer has : ip link show

Install xmind on your desktop without using yum: 
sudo apt install ./Xmind.deb


Get the last 5 entries of /var/log/messages :
tail -n 5 /var/log/syslog


Get the first 5 entries of /var/log/messages :
head -n 5 /var/log/syslog


Get log entries of /var/log/messages which is printed within today :
ls -ltc --time-style=+%D


Get number of lines in /var/log/messages : w -l


Get the number of unique lines in /var/log/messages :
uniq


Sort directory/file list based on time inside your home directory :
find / -type f -printf "\n%AT %p" | head -n 10


Access your friends machine using ssh and copy a file there :
ssh
ssh localhost
sudo apt-get install openssh-server ii      
sudo service ssh status
ssh localhost


Rename the directory my_group to my_group1 :
mv my_group my_group1


View partition information : sudo fdisk


Get the total sizes of sub directories inside /var using single command : sudo du -shc /var/*


Change system date to yesterday using command line : 
sudo date -s '2020-07-26 12:15:35'


Remove the directory my_group1 :
rmdir my_group1
 
Check the utilization of the following in your desktop
      
        a. CPU : top

        b. Memory : vmstat
                    free -m
        
        c. Disk : df
                  df -BM
 
 
 
 
 

What is YUM?

YUM is an automatic updater and package installer/remover for rpm servers. It automatically computes dependencies and figures out what things should occur to install packages. It also makes it easier to maintain groups of machines without having to manually update each one using rpm.

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