Basics of Linux Commands (Day 03)

Basics of Linux Commands (Day 03)

1. To view what is written in a file :

To view the content of a file we can use the "cat command" like this :

$ cat <filename>

$ cat test.txt

2. To change the access permissions of files:

"chmod" is the command which stands for change mode, used to change the file permissions.

0” represents “no permission”.

  • 1” represents “execute permission”.

  • 2” represents “write permission”.

  • 4” represents “read permission”.

    We can give permissions to the Owner, Group and Others of a file. So if I want to give all permissions to the Owner, read and execute permissions to the group, and only read permission to others so it will be like this:

  • $ chmod 754 <filename>

3. To check which commands you have run till now :

To check all previously executed commands we use the "history command"

$ history

4. To Remove a directory/folder :

we use the "rmdir command" to remove a directory,

$ rmdir <directory name>

5. To create a fruits.txt file and view the content:

To create a file we use the touch command and to view the content(if any) of a file we use the cat command :

$ touch fruits.txt

$ cat fruits.txt

6. Add content in devops.txt (One in each line) - Apple, Mango, Banana, Cherry, Kiwi, Orange, Guava :

To do the whole task once at a time we can use the echo command, as it will add the contents and also print the content too.

$ echo "Apple" >> devops.txt
$ echo "Mango" >> devops.txt
$ echo "Banana" >> devops.txt
$ echo "Cherry" >> devops.txt
$ echo "Kiwi" >> devops.txt
$ echo "Orange" >> devops.txt
$ echo "Guava" >> devops.txt

7. Show only the top three fruits from the file:

Use the head command to show the top three from the file as :

$ head -3 <file name>

$ head -3 devops.txt

8. Show only the bottom three fruits from the file:

Use the tail command to show the top three from the file as :

$ tail -3 <file name>

$ tail -3 devops.txt

9. To create another file Colors.txt and view the

content :

To create a file we use the touch command and to view the content(if any) of a file we use the cat command :

$ touch Colors.txt

$ cat Colors.txt

10. Add content in Colors.txt (One in each line) - Red, Pink, White, Black, Blue, Orange, Purple, and Grey :

To do the whole task once at a time we can use the echo command, as it will add the contents and also print the content too.

$ echo "Red" >> Colors.txt
$ echo "Pink" >> Colors.txt
$ echo "white" >> Colors.txt
$ echo "Black" >> Colors.txt
$ echo "Blue" >> Colors.txt
$ echo "Orange" >> Colors.txt
$ echo "Purple" >> Colors.txt

$ echo "Grey" >> Colors.txt

11. To find the difference between the fruits.txt and Colors.txt files:

We can use the diff command to check the difference between two files like :

$ diff <filename 1 > <filename 2 >

$ diff <fruits.txt > <Colors.txt>