13,420
edits
Changes
→INVESTIGATION 2: USING VARIABLES IN SHELL SCRIPTS
# Issue the following linux command to change to the Bourne Shell (a different shell than the default Bash):<br><span style="color:blue;font-weight:bold;font-family:courier;">sh</span><br><br>
# Issue the following linux command to confirm you are in the Bourne Shell:<br><span style="color:blue;font-weight:bold;font-family:courier;">echo $SHELL</span><br><br>You should see the output of the command that you are located in the Bourne Shell.<br><br>
# Re-run Run your shell script: <span style="color:blue;font-weight:bold;font-family:courier;">./hello</span><br><br>What shell does the shell script indicate is running?<br>You should notice that this script is being run in the Bourne shell.<br><br><br><br>Although your shell script should work, it is recommended to force your shell script to run in a specific shell. This helps prevent your shell script encountering errors when run in the incorrect shell (i.e. syntax not recognized in a specific shell).<br><br># Edit your '''hello''' shell script using a text editor.<br><br># Insert the following line at the '''beginning''' of the '''first''' line of your hello file:<br><span style="font-family:courier;">#!/bin/bash</span><br><br>This is referred to as a she-bang line. It forces the script to be run in the Bash Shell. When your Bash Shell script finishes execution, although the you are returned to your current shell that you are using (which in our case in Matrix, is still the Bourne Bash shell).<br><br># Save your editing changes and exit your text editor.<br><br>
# It is a good idea to rename your shell script to include an extension to indicate that the file is a Bash Shell script file. <br>Issue the following linux command to rename your shell script file:<br><span style="color:blue;font-weight:bold;font-family:courier;">mv hello hello.bash</span><br><br>
# Run your renamed shell script for confirmation by issuing:<br><span style="color:blue;font-weight:bold;font-family:courier;">./hello.bash</span><br><br>
