One of the most basic and useful program tools in the shell itself. Its also a powerful programming environment

Step 1. Type the following command to create a new file:
     Code:

Step 2. Type the following lines:

     Code:Press ENTER to move the cursor to a new line and press CTRL-D. At this point, the file new_script contains a series of shell commands.

Step 3. Examine the file to be certain it is correct:

     Code:If there are errors, remove the file new_script and return to step 1 to create it again.

Step 4. Try to run the script by entering its name:

     Code:It doesn't run because its not executable.

Step 5. Display the permission of the file by entering:

     Code: Notice that the file is not executable. You must make it executable.

Step 6. Type the following command to make new_script executable:

     Code:

Step 7. To see the new permission, enter:

     Code:You now have execute permission, as well as read and write permissions for the file.

Step 8. Execute the new script by typing its name:

     Code:All the commands that you typed into the file are executed, and their output is sent to the screen.

Step 9. If you receive an error message such as:

     Code:Type the following:
     Code:This command line tells the shell exactly where to find the shell script, new_script, in your current directory knows as "dot."