How to edit a text file in my terminal

Try this command:

sudo gedit helloWorld.txt

it, will open up a text editor to edit your file.

OR

sudo nano helloWorld.txt

Here, you can edit your file in the terminal window.

Open the file again using vi. and then press " i " or press insert key ,

For save and quit

  Enter Esc    

and write the following command

  :wq

without save and quit

  :q!