Some Usefull linux commands

Which command is used to view what's written in the file?
```
  cat file_name
```

Which command is used to change the access permissions of files?

  chmod <options> file_name
      eg: chmod 777 test1.txt 
      eg: chmod u+rwx test1.txt

Which command is used to check which commands you have run till now?
```
  history
```

Which command is used to remove a directory/ Folder?

  rmdir directory_name
  rm -r directory_name

List the commands to create a fruits.txt file and view the content of it.

--> For creating the fruits.txt file we have several ways like touch and cat. and for viewing the contents we can use cat with the file name.
```
  # for creating the file .
  touch fruits.txt
  cat > fruits.txt
  # for veawing the contents of the files.
  cat fruits.txt
```
Write the commands to add content in devops.txt (One in each line) - Apple, Mango, Banana, Cherry, Kiwi, Orange, Guava.
```
  cat > file_name
```

Write the commands to show only the top three fruits from the file.

  head -n file_name
  # here "n" is basically number of lines .

Write the commands to show only the bottom three fruits from the file.

  tail -n file_name
  # here "n" is basically number of lines .

Write the commands to add content in Colors.txt (One in each line) - Red, Pink, White, Black, Blue, Orange, Purple,Grey.

--> If we are using vim editor then write "vim file_name" into cmd then press enter. after entering into vim editor now press " i " key to enable input mode. after content writing press :wq for save and exit from the vim editor.
```
   vim file_name   # press enter
```
How To find the difference between fruits.txt and Colors.txt files.
```
  diff  file_name1 file_name2
```