What is Shell Script
A shell script is a list of commands and control flow statements that is run by the Unix and Linux Shell also known as a command line interpreter. You can perform various system operations through shell scripts such as Reading/Writing files, Redirections, Pipes and various automation.
Create shell script File
Every shell script is composed in the text-based file called shell script file with an extension of .sh. You can create any filename according to the purpose of the script, the name doesn’t matter. So use any text editor of IDE for creating shell script files.
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vim first_script.sh
The content inside the file.
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1 #!/bin/bash
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3 echo "This is first shell script"
4 echo "I'm listing files in the current directory through a shell script, here"
5 ls -la
Script explained
- Line: 1 #!/bin/bash is known as Shebang, Interpreter for execution under UNIX / Linux operating systems.
- Line: 2 Blank line for more readability.
- Line: 3,4 echo is a bash builtin used to write contents to standard output(Terminal).
- Line: 5 ls -la is another bash built-in command to display a list of the information of the files.
How to run the shell script
Before running the shell script need to give execution permission for our first shell script, otherwise, the shell script won’t be executed as a script.
Use the Unix chmod command to give execution permission for the file.
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chmod u+x first_script.sh
ls -la first_script.sh
-rwxrw-r-- 1 tux tux 0 Aug 9 10:05 first_script.sh
Time to execute 💥
To execute the Shell script, you can simply call the shell script from your favorite terminal program.
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./first_script.sh
Or you can try to execute explicitly with a Bash interpreter.
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bash first_script.sh