Create an executable script¶
Objectives
- Create an executable bash script
Notes for teachers
Teaching goals:
- The learners demonstrate they can create an executable script
Schedule:
gantt
title Lesson plan Command line
dateFormat X
axisFormat %s
Prior knowledge: prior, 0, 5s
Theory: theory, after prior, 5s
Exercises: crit, exercise, after theory, 25s
Feedback: feedback, after exercise, 10s
Why?¶
Instead of typing commands in the terminal all the time, you can put these in a file. Such a file, called a script, can then be shared.
Procedure¶
Creating an executable script has two steps:
- Create a script
- Allow the script to execute
As an example, we create a script, called do_it.sh
:
Why use a .sh
file extension?
Using .sh
as a file extension a social convention
for how a Bash script is called,
as (1) sh
is short for 'shell',
(2) Bash is short for 'Bourne Again Shell'.
A 'shell' in this context is a program
that allows working with an operating system.
As an example, copy-paste this content into the script:
What does this program do?
The first line is called the shebang, and indicates this is a Bash script.
The second line displays the text between double quotes.
Save and close nano
.
- Use
CTRL-O
to start saving your file, then edit the filename, then press enter - Use
CTRL-X
to exit
Use chmod to make the file executable:
+x
can be read as: 'add the right to execute'
Create read-only files
If you want to protect your data from being modified accidentally,
chmod
can create read-only files,
by removing the writing rights using chmod -w
.
Exercises¶
Exercise 1: create an executable script¶
- Create a file called
do_it.sh
usingnano
- Edit the file
do_it.sh
to have the content below:
- Make the script executable
- Run the script