IT 244: Introduction to Linux/Unix
Homework 8

Due Sunday, April 01st 11:59 PM

Deliverables

1. A shell script named hw8.sh that performs the operations listed below.
   This file should be in an hw8 directory inside your hw directory inside your it244 directory.
   100 points

Requirements

• Create an hw8 directory in your hw directory inside your it244 directory
• Go to the hw8 directory and run Unix commands that will execute the steps below
• When you have a command line that does what the step asks you to do, paste it into hw8.sh using nano or any other text editor
• When you have completed all the steps, create an echo statement before the commands for each step, that will print the step number to the terminal

Testing

• The script hw8.sh must have the format specified in this document
• Scripts that do not follow the rules specified in the document mentioned above will will have points deducted from their score
• Be sure to test your script and correct any errors you find
• You will lose 5 points for each error that occurs when running your script
• To run your script and see only the error messages run the following command

  ./hw8.sh  >  /dev/null

Steps for Script

1. Perform the following actions
   • Run ls on a file that does not exist
   • Run ls on the same file, but redirect Standard Error to /dev/null
   • Run ls on the same file, but redirect Standard Error to errors.txt
   • Print errors.txt to the terminal
   Run one command for each of the items above.
2. Using 3 commands on the same command line
   • Go to your home directory
   • Run ls
   • Return to your hw8 directory
3. Copy bother10.sh from /home/tsoro/course_files/it244_files to your hw8 directory.
   Write a single command line that
   • Runs bother10.sh in the background sending the output to /dev/null
   • Runs bother10.sh in the background sending the output to /dev/null
   • Runs bother10.sh in the background sending the output to /dev/null
   • Runs ps in the foreground
4. Using the directory stack mechanism do the following
   • Go to your home directory
   • Show your position in the filesystem
   • Go to my home directory
   • Show your position in the filesystem
   • Return to your home directory
   • Show your position in the filesystem
   • Return to you hw8 directory
   • Show your position in the filesystem
5. Do the following
   • Create the local variable foo and assign it the value "FOO"
   • Create the global variable bar and assign it the value "BAR"
   • Write a single command that will print the values of foo and bar
6. Do the following
   • Copy print_foo_bar.sh from /home/tsoro/course_files/it244_files to your hw8 directory
   • Run print_foo_bar.sh
   The value of foo will not print because it is local to the login shell and cannot be seen in a subshell.
7. Do the following
   • Create the global variable my_city and assign it the name of the town you live in
   • Write an echo statement that uses my_city to tell me where you live.
     The entire statement must be quoted.
8. Print the value of the keyword shell variable whose value is a list of all the directories Bash will search to find an executable file with the same name as the command you typed on the command line.
9. Print the value of the keyword shell variable whose value is the absolute pathname of your default shell.
10. Run a command that will show you all your global variables.