Unix commands can be placed into a file just like DOS commands. The commands in the file are executed in sequence as though you were typing each one from the command line and pressing enter after the command. The commands become a user-defined "Unix command".

To create a shell script,

1. Open your favorite editor (nano or vi) and create a file with any name you choose. The filename will become the shell script's name and thus the name of a user-defined unix utility.
2. Good scripting practice suggests that the first line of the script be:
   #!/bin/sh
   This Unix command tells the interpreter that is running the command, which Unix shell to use. Different shells (Bash, bourne, cshell) have different syntax. For the Bash and bourne shell use /bin/sh, for the cshell use /bin/csh/. A new shell will begin executing and the commands in your script will be executed in this new shell.

   type in
   echo hello
   echo my name
   echo "my name"
   echo $1

   Save the file

   Change the permissions on the file so that you can execute the file.
   chmod u+x file

   Issue the command file

   Issue the command file bye

   Help with the example

Give this a try ... write a script that outputs:
Hi username happy day of the week

1. Using the PID
2. Built in shell variables
3. Better use of PID
4. Use /tmp
5. Cleaning up tempfiles(and read)
6. Setting variables to result of commands
7. the set command
8. more of the set command