This document discusses bash scripting. Bash scripts allow Linux commands to be stored in plain text files with a .sh extension and executed like a program. The first line must start with "#!". Variables can be declared and initialized, and commands like echo can display variable values. Control structures like if statements, for loops, and while loops allow conditional execution. Functions can be defined to group and reuse code.

1. Lab 7 – Bash Script CIE 302 - Operating
systems

2. What is bash scripting?
Bash script: a plain text that contains a series of commands, which
can be used to write Linux commands in the terminal.
Anything you can run normally on the command line can be put into
a script and it will do exactly the same thing.
Bash scripts an extension of .sh (myscript.sh). However, Linux is an
extensionless system so a script doesn't necessarily have to have this
characteristic in order to work.

3. How to execute a bash script?
 ./script → it will execute the script file, as
a new child process within the
bash/terminal.
 to grant permissions, to execute file:
chmod 755 script1 ⇔
(rwxr-xr-x) The file's owner may read, write, and execute the file. All
others may read and execute the file.

4. Script format
#!/bin/bash ⇔ The first line in code, must start with “#!”.
# A sample Bash script ⇔ comment line, not executed.
echo Hello World! ⇔ actual command that could be directly written in the terminal.

5. Variables
To declare a variable:
$a, $A, $a1A.
To initialize a variable
 a=4
To display the variable and its value
 echo $a
Variable substitution
var='Hello Student'
text=" $var Ahmed"
echo $text

6. If statements

7. If statements

8. For loop

9. While loop

10. Functions
To declare a variable:
$a, $A, $a1A.
To initialize a variable
 a=4
To display the variable and its value
 echo $a
Variable substitution
var='Hello Student'
text=" $var Ahmed"
echo $text