IT 244: Introduction to Linux/Unix
Class 7 Exercise, Tuesday, February 23rd

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 ex07 directory
  

      mkdir  ex07

• Go to your ex07 directory
  

      cd  ex07

Filename Extensions

• Create the text file foo.txt with a text editor
  

      nano foo.txt

• Add some text
  
  Save and quit.
  
  
• Run cat on the file
  

      cat foo.txt

  cat prints the file to the terminal.
  
  
• Change the extension of foo.txt
  

      mv foo.txt foo.xyz

• Open the renamed file with nano
  

      nano foo.xyz

  nano opens the file without difficulty.
  
  nano does not care about the extension.
  
  
• Change some text in the renamed file
  
  Save and quit.
  
  
• Run cat on the renamed file
  

      cat foo.xyz

  cat does not care about the extension.

Create a typescript File

• Make sure you are in your ex07 directory
  

      pwd

  If the result of running this command is not

      ~YOUR_UNIX_USERNAME/it244/ex/ex07

  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 ex07 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.

The Hierarchical Filesystem

• Find your current location
  

      pwd

  You should be in the ex07 directory inside your ex directory of your it244 directory.
  
  
• Go up one level to your parent directory
  

      cd ..

  .. means the directory one level up.
  
  
• Look at your current location
  

      pwd

  You have moved up one level.
  
  
• Go to the root directory
  

      cd /

• Look at your current location
  

      pwd

  You are at the top of the filesystem.
  
  
• Look at the directories inside the root directory
  

      ls

  Notice that the home and courses directories are subdirectories of the root directory.
  
  
• Return to your home directory
  

      cd

• Look at your current location
  

      pwd

  Your home directory is inside the directory named home, which is, itself, under the root directory, /.
  
  
• Return to the ex07 directory inside your it244/ex directory
  

      cd it244/ex/ex07

• Check you current location
  

      pwd

Filenames

• Run stat to get some information about the Linux host
  

      stat -f /home

• Run stat with grep to learn the largest filename possible
  

      stat -f /home | grep Namelen

• Create a file with spaces in the name
  

      touch 'hello there'

  If you did not put "hello there" in quotes, you would create 2 files, hello and there.
  
  
• List the contents of your current directory
  

      ls

  It looks like you have created two files.
  
  
• Perform a long listing on your current directory
  

      ls -l

  Now you can see that there is only one file.
  
  
• Remove the file you just created
  

      rm 'hello there'

• Make sure the file is gone
  

      ls 

Case Sensitivity

• Create the file foo.txt
  

      touch foo.txt

• Look at the contents of the directory
  

      ls

• Create another foo.txt file
  

      touch foo.txt

• Look at the contents of the directory
  

      ls

  You only have one foo.txt file since you can only have one file with a given name in any one directory.
  
  
• Create the file Foo.txt
  

      touch Foo.txt

• List the files in your current directory
  

      ls

  You have two files since, as far as Unix is concerned, foo.txt and Foo.txt are totally different file names.
  
  
• Create some new files
  

      touch fOO.txt FOO.txt FOO.TXT

• List the contents of your current directory
  

      ls

  You should see the files you just created since they have different capitalizations.
• Remove all .txt files from your ex07 directory
  

      rm  *.txt

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 ex07 directory
  

      cd ~/it244/ex/ex07

• Make sure you are in your ex07 directory
  

      pwd

  If not, see me.
  
  
• Create the script ex07.sh
  

      nano  ex07.sh

• Write into this file commands from most of the sections above
  
  
  Copy all the commands from the sections The hierarchical filesystem to Case sensitivity Skip the section Filename extensions.
  
  
• Save this file
  
  Save and quit.
  
  
• Test the script
  

      bash  ex07.sh

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