Erle Robotics Unix Introduction Gitbook Free

Practical introduction to vim

We are going to familiarize with the vim text editor by doing some practical examples.For now on, we are working with erlerobot.

First, go to erle home and create a directory, called linuxpractice, where we are going to save the files. Create and open with vim a .txt file, using vi.

We are going to number the lines and show the mode we are working on, type :

: (press enter)
(you are in the ex mode)
:set showmode (press enter)
:set nu (press enter)

Press i and type what you want. Remember: press enter to continue writing in the next line. When you finish typing press escape and ZZ for save and leave.

If you type

cat example1.txt

You can see what you have written in the file:

Open again the file by typing:

vi example1.txt

After opening it:

:(press enter)
:set nu (press enter)
:set showmode(press enter)

Question: What should be the result of doing...?

:5 (press enter)
dd

Question: What should be the result of doing...?

:1(press enter)
yy
:4
p

Leave and save using

:(press enter)
:wq (press enter)

Now we are going to remove the wrining permissions. This means that example1.txt should be a readonly file.

chmod 444 example1.txt

If you open the file with vi ,you will find a warn message at the end of the file:

Type

:(press enter)
:3 (press enter)
dd (press escape)
:5 (press enter)
R
This is the end of the file for now.

The aspect of the file is:

If you try to save and leave using:

(press escape)
ZZ

you get this message:

E45: 'readonly' option is set (add ! to override)

You can overwrite the file and save the changes forcing:

(press escape)
:w!

Exercise:

Create a file in linuxpractice directory and call it erle_description.txt Write a short description of erlerobot (3 lines). After that leave two blank lines and write your name. Save the changes and leave.

If you do catthe result should be something like this:

Now try to delete the line 4 and to write your name in the first line. The final result is the following one: