Steps to execute a shell script in Linux

The procedure is as follows:

1. Create a new file called demo.sh using a text editor such as nano or vi in Linux: nano demo.sh
2. Add the following code:
   #!/bin/bash
   echo "Hello World"
3. Set the script executable permission by running chmod command in Linux: chmod +x demo.sh
4. Execute a shell script in Linux: ./demo.sh

Let us see all steps in details.

Step 1 – Open the terminal

To write a shell script, open the terminal app. Hit the keyboard shortcut Ctrl-Alt+T:

Step 2 – Write the shell script using an editor

Type the following command to write a shell script:
nano demo.sh
OR
vi demo.sh

#!/bin/bash
# My first shell script
echo "Hello $USER"
echo "Today is $(date)"
echo "Bye for now"

To Save and close the file in nano press CTRL+X and when prompted choose Y (Yes) to save the file and followed by the Enter key:

Step 3 – Make the shell script executable

Let us verify newly created file, run [nicmd name=”ls”] and cat command:
ls -l demo.sh
cat demo.sh
To set executable permission, run the following chmod command:
chmod +x demo.sh
Verify permissions:
ls -l demo.sh

Step 4 – Execute the shell script in Linux

Now we have shell script named demo.sh. But, how do you run it? Try:
./demo.sh
The . refers to the current directory. Another option is to specify the full path:
/path/to/demo.sh
/home/vivek/demo.sh
~/demo.sh

Conclusion

For more info see Linux Shell Scripting Tutorial and bash command man page:
man bash
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