Day 3: Basic Linux Commands

To View the contents of a file

Cat - This Linux command allows you to view the contents of a file

Simply type cat filename & Press Enter

Replace "filename" with the name of the file you want to view.

Change access permissions of files

chmod -To modify the access permissions of a file, use the chmod command followed by the permission code and the file name.

The permission code consists of three digits representing read (4), write (2), and execute (1)permissions for the owner, group, and others, respectively.

Simply type chmod 644 filename& Press Enter

For example - To give read and write permissions to the owner (4 for read + 2 for write = 6) and read-only permissions to the group (4) and others (also 4):

Here's a breakdown of the numeric representation as per the command

The first digit (6) represents the permissions for the owner (read + write). The second digit (4) represents the permissions for the group (read). The third digit (also 4) represents the permissions for others (read). Replace "filename" with the name of the file you want to modify. After running this command, the owner will have read and write permissions, while the group and others will have read-only permissions.

Check your command history

history -To view the list of commands you have run in the terminal session history.

Simply type history& Press Enter

This will display a numbered list of commands you executed during the current session.

Remove a directory/folder

rm - To remove a directory/ Folder.

Simply type rm filename/directoryname & Press Enter

Create a fruits.txt file and view its content

touch - To create an empty file named "fruits.txt,"

cat -To view the contents of the file (we discussed earlier)

Simply type touch filename & Press Enter

then ,type cat filename & Press Enter

Add content in fruits.txt (One in each line)

Vim - To open a file to add content

Simply type vim filename Press Enter

Inserting Text: To start inserting or editing text within the file, press i for insert mode. You can then type or modify text as needed.

Saving and Exiting: To save the changes and exit vim, press Esc to ensure you are in normal mode, and then type :wq or ZZ (Shift + zz) Press Enter

To Show only the top three fruits from the file

head - To display the top lines of the file

Simply type head -3 filename Press Enter

you can also use the head command with the -n option

To Show only the bottom three fruits from the file

tail -To display the last lines of the file,

Simply type tail -3 filename Press Enter

you can also use the tail command with the -n option

To create another file with content in Colors.txt (One in each line) and to view the content.

We already discussed this earlier touch ,vim & cat command

To find the difference between fruits.txt and Colors.txt file

diff - To compare the contents of two files and find the differences

Simply type diff filename1 filename2 Press Enter

The diff command will display the lines that are different between the two files, if any.

I hope you found this blog helpful!

Happy learning!