Vi Commands

To create a shell script:

1. Use a text editor such as vi. Write required Linux commands and logic in the file.


2. Save and close the file (exit from vi).


3. Make the script executable.


4. You should then of course test the script, and once satisfied with the output, move it to the production environment.


5. The simplest program in Bash consists of a line that tells the computer a command. Start up your favorite text editor (such as vi):

vi hello.sh

Essential Vi Commands

• Open a file:

vi filename

• To go into edit mode:

press ESC and type I

• To go into command mode:

press ESC

• To save a file

press ESC and type :w fileName

• To save a file and quit:

press ESC and type :wq

OR

press ESC and type :x

• To jump to a line:

press ESC and type :the line number

• To Search for a string:

Press ESC and type /wordToSearch

• To quit vi:

Press ESC and type :q

Save the following into a file called hello.sh:

#!/bin/bash
echo "Hello, World!" 
echo "Knowledge is power."

Save and close the file. You can run the script as follows:

 ./hello.sh

Sample outputs:

bash: ./hello.sh: Permission denied

Saving and Running Your Script

The command ./hello.sh displayed an error message on the screen. It will not run script since you've not set execute permission for your script hello.sh. To execute this program, type the following command:

chmod +x hello.sh
./hello.sh

Sample Outputs:

Hello, World!
Knowledge is power.