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Getting Started With Linux And Unix Basic Commands

What is UNIX?

Unix is a multiuser operating system developed by Ken Thompson and Dennis Ritchie in 1970 at AT&T bell lab. Unix is proprietary software. Meanwhile, no one can duplicate this operating system because the source code is reserved for the company. Unix is rigid with hardware and mainly used for server-based machines. Unix has a high cost and capacity with limited versions because only companies can build new versions.

Versions of Unix Based Operating Systems: BSD, Iris, HP-UX, AIS

What is Linux?

Linux is the most popular operating system. Linux is open source operating system why which is very secure to use and we didn’t need any anti-virus for Linux as compared to Windows. Linux was delivered on September 17, 1991, by Linus Torvalds.

What is the Difference between Unix and Linux?

Basic commands of Unix and Linux that everyone should know

lsLists file in a directory
rmDeletes files in a directory
mvMove a file to a different location
catDisplay the content of the file
rmdirRemove a directory or subdirectory
sudoShort for ‘super user do‘ sudo is the most popular command
mkdirCreate a directory or subdirectory
pwdShow the name of the current directory
telnetConnect to a remote computer
whoDisplay users that are logged on
echoUsed to display text or string and mostly used in bash or script files.
sedPerform lots of functions on file like searching, find and replace, insertion or deletion.

Let’s go deeper into each command:


Is a command used for displaying directory lists in alphabetical order? When you type Is without any parameters it will show your default directory.

Example: ls

Result – Displaying you a list of working directories in alphabetical order.

Example: ls -l

Result – It will display you a ‘long listing’ of files in your directory like file names, long lists of protection information, numbers of characters in the file, and the date and time of the last change to the file.

Example: ls -a

Result – cause all your files will be listed including hidden files and currently working files.


rm command used for deleting specific files that have been entered by space with the file name.

Example: rm newfiles

Result – deletes the file named “newfiles”.

Example: rm newfile oldfile

Result – deletes two files named “newfile”, ”oldfile”.

Example: rm new*

Result – deletes all files that content prefix new.


mv commands can change one or more file names.

Example: mv oldfile newfile

Result Changes the name of the document “oldfile” to “newfile.” Just a single record will exist.

Example: mv oldfile canister/newfile

Result  Changes the name of the document “oldfile” to “newfile” and places it in the registry/container. Just a single record will exist.


cat command will display the content of the files.

Example: cat newfile

Result – displaying the contents of ‘newfile’ in your terminal.

Example: cat newfile oldfile

Result – now it will display two file’s content – “newfile”, “oldfile” as one continuous display.

Concatenating (combining) files and putting them into another file can also be done with the cat command. The contents of the previous file are permanently lost when files are concatenated with one another.

Example: cat fileone filetwo filethree >newfile

Result – Now it will link together three files – “fileone” , ”filetwo” ,  ”filethree”  into a new file called “newfile”. The original file hasn’t changed.


rmdir commands are for removing empty directories on various operating systems.

Example: rmdir mydir

Result – Remove the directory mydir, if it’s empty.

Example: rmdir dir1 dir2 dir3

Result – Remove the directory “dir1, dir2, dir3”, if it’s empty, if it’s not empty an error will be printed for that directory, and the other will be removed.


There are some commands that need elevated rights to run on a Linux system. It would be best if you ran these as a System Administrator. The su command changes the shell so that it is used as a super user. Until you use the exit command, you can continue to be the super-user.

You can also add an option, such as:

Example: Sudo -k

Result – reset-timestamp invalidates the timestamp file.

Example: Sudo -g

Result – group=group runs commands as a specified group name or ID.

Example: Sudo -h

Result – host=host runs commands on the host.


mkdir commands are used to create a new directory file in working files. These commands can create multiple directories at once as well as the permissions of the directories.

Example: mkdir newfile

Result – Create a new file which name is “newfile”

Example: mkdir ~/myfiles

Result – Create a home directory in your home directory, specified here “tilde” (~) to represent your home directory.


Pwd command will print the full path name of the current working directory to the understood output. All directories are separated by / (Slash).

Example: pwd

Result – Print the name of the working directory. If any of the subdirectories in the path are symbolic links, and you used the symlink names when changing to the directory, the symlink names are printed. Example output:- /home/hope/mysymlink/mydir

Example: pwd -p

Result – Print the name of the working directory using the actual name of the directory, even if any symlink names were used when changing to the directory. For example :- /home/hope/actual_directory_name/actual_subdirectory/mydir


who commands without any argument display the system information like user name, logging time, the terminal of the user, and also the hostname of the system.

Example: Who

Result – Display the name of the user that logged on, the line number of the terminal, the time at which the user logged in to the system, hostname of the user who logged in.


“Echo” is one of more highest commands of Linux used to show text or string and for the most part utilized in bash or script files. It helps to portray natural variables present in the framework. The syntax of the “echo” command is given beneath:

Example: echo “Introducing echo”

Result – It will print text that is given into it (Introducing echo).

echo “text” >> [filename] Using this syntax we can move the text into a file

Example: echo “Important data” >> information.txt

Result – It will import text(Important data) into a file name information.txt.


SED command in UNIX represents stream editor and it can perform heaps of capabilities on files like looking, finding, and replacing addition, or erasure. However, the most well-known utilization of the SED command in UNIX is for a replacement or for finding and supplanting. By utilizing SED you can alter files even without opening them, which is a much speedier method for finding and supplanting something in a file, than first opening that file in VI Editor and afterward evolving it.

Example: sed ‘s/Unix/Linux/’ skilltectfile.txt

Result – Replacing or substituting string: Sed command is generally used to Replace the text in a file. sed command replaces the word “Unix” with “Linux” in the file(skilltectfile.txt).

What We Get From This Blog

Topics we learned in this blog are “Getting Started With Linux And Unix Basic Commands”, “What is the difference between Linux and Unix?” and “Basic commands of Unix and Linux that everyone should know ”.

Article by Harsh Shrivastav

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