IT 244: Introduction to Linux/Unix
Class 8 Exercise, Thursday, 02/25-03/02

Log in to pe15

• Run the ssh client
  

  Use the values in the table below to connect to pe15.

  ssh configuration parameter	value
  protocol	ssh
  ssh version	2
  ssh port	22
  host	pe15.cs.umb.edu
  user name	your Unix username
  Authentication method	password

  
  
• Enter your password

  A dialog box will appear on the screen into which you must type the password for your Unix account.

Directory for this Exercise

• Make sure you are in your home directory
  

      cd

• Go to your it244 directory

      cd  it244

• Go to your ex directory
  

      cd  ex

• Create an ex08 directory
  

      mkdir  ex08

• Go to your ex08 directory
  

      cd  ex08

Create a typescript File

• Make sure you are in your ex08 directory
  

      pwd

  If the result of running this command is not

      ~YOUR_UNIX_USERNAME/it244/ex/ex08

  where YOUR_UNIX_USERNAME is the name you created for your Unix account, see me.
• Run the script command
  

      script --flush

  This will create a typescript file in your ex08 directory.
  
  You must perform the remaining steps in this exercise while script is still running.
  
  If you make a mistake, simply try again.
  
  Do not exit the script session until you have finished all the steps in this exercise.

Hidden Files

• Return to your home directory
  

      cd

• Confirm that you are in your home directory
  

      pwd

• Look at your hidden files
  

      ls  -a

  These files configure various settings in your Unix environment.
  
  

Startup Files

• Go to my home directory
  

      cd  ~ckelly

• Look at my "invisible" files
  

      ls  -a

• Look at the contents of my .bash_profile file
  

      cat  .bash_profile

  This file runs other files that customize my Unix environment.
  
  
• Look at the contents of some of the other files
  

      cat  .bashrc

  What you see here may not mean much to you now.
  
  But it will later in this course.

Absolute Pathnames

• Go to my course_files/it244_files directory using an absolute pathname
  

      cd  /home/ckelly/course_files/it244_files

  You can use this pathname anywhere in the filesystem and will always refer to the same directory.
  
  
• Determine your location
  

      pwd

  Notice that pwd always returns the absolute pathname of your current directory.
  
  
• Go to my home directory using an absolute pathname
  

      cd  /home/ckelly

• Verify that you are in my home directory
  

      pwd

Tilde  ~ 

• Return to your home directory using tilde  ~ 
  

      cd  ~

• Determine your current location
  

      pwd

  You should be in /home/YOUR_UNIX_ID
  
  
• Go to my home directory using tilde  ~ 
  

      cd  ~ckelly

• Determine your current location
  

      pwd

  You should be in /home/ckelly
  
  
• Go to your it244 directory using tilde  ~ 
  

      cd  ~/it244

• Determine your current location
  

      pwd

  You should be in /home/YOUR_UNIX_ID/it244.
  
  Notice that, although short, ~/it244 is an absolute pathname and can be used anywhere within this filesystem.

The  .  in a Directory

• Go to your ex08 directory in your it244/ex directory using tilde  ~ 

      cd  ~/it244/ex/ex08

• Look at the entire contents of your ex08 directory
  

      ls  -a

  Notice that you have a  .  and a  .. entry.
  
  The  .  stands for your current directory.
  
  
• Create a file named foo.txt
  

      touch  foo.txt

• Create a test directory
  

      mkdir  test

• Enter the test directory
  

      cd  test

• Determine your current location
  

      pwd

• Copy foo.txt from the parent directory into your current directory
  

      cp  ../foo.txt  .

  You use  .  to specify the current directory and  ..  to specify the parent directory.
  
  
• Check that the copy operation worked
  

      ls

• Make sure you are in your test directory
  

      pwd

• Remove everything from your test directory
  

      rm *

• Go back to your ex08 diretory
  

      cd ..

• Remove the test directory
  

      rmdir  test

Relative Pathnames in the Current Directory

• Go to the course_files/it244_files directory in my home directory
  

      cd  ~ckelly/course_files/it244_files

• Check your location
  

      pwd

• List the contents of this directory
  

      ls

• Display the contents of fruit.txt
  

      cat  fruit.txt

  Since fruit.txt is in your new current directory, its pathname is simply the filename.

Relative Pathnames in a Subdirectory

• List the content of the current directory
  

      ls

• List the contents of the dir1 directory using a relative pathname
  

      ls  dir1

• List the contents of the dir2 directory using a relative pathname
  

      ls  dir1/dir2

• Display the contents of foo.txt inside dir2 using a relative pathname
  

      cat  dir1/dir2/foo.txt

Relative Pathnames above the Current Directory

• Go to the dir1/dir2 directory using a relative pathname
  

      cd  dir1/dir2

• Display your current location
  

      pwd

• Display the contents of the course_files/it244_files directory using a relative pathname
  

      ls  ../../

• Display the contents of the root directory using a relative pathname
  

      ls  ../../../../../..

Relative Pathnames neither Above nor Below your Current Directory

• Look at the contents of my home directory using a relative pathname
  

      ls  ../../../..

• Look at the contents of my class notes directory for this course
  

      ls  ../../../../public_html/teaching/it244/

• Look at the first 10 lines of my notes for today's class
  

      head  ../../../../public_html/teaching/common/exercises/linux/intro/exercise_08.html

End your script Session

• Exit from your script session
  

      exit

  You need to do this or the typescript file will never be created
• Look at the contents of the typescript file
  

      cat  typescript

Bash Script for this Exercise

• Go to your ex08 directory
  

      cd ~/it244/ex/ex08

• Make sure you are in you ex08 directory
  

      pwd

• Create the script ex08.sh
  

      nano  ex08.sh

• Write into this file the commands you used above
  
  Include Unix commands from the section Hidden files to the section Relative pathnames neither above nor below your current directory.
  
  
• Save this file
  
  Save and quit.
  
  
• Test the script
  

      bash  ex08.sh

  Fix any errors you find.
  
  If you have trouble, see me.