INTRODUCTION TO UNIX
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                        lab 5


       1. examine the output for the following commands:

      a.
      grep your-userid /etc/passwd | cut -f1

      b.      
      grep your-userid  /etc/passwd | cut -f1 -d:


          What is the difference between them.


       2. Create a file "lab5-input" with the following line:

          abcd:efgh!12345:xtyuopw!


       3. Type the following commands and examine the output


          a. cat lab5-input | cut -f1 -d:
          b. cat lab5-input | cut -f2 -d:
          c. cat lab5-input | cut -f1 -d!
          d. cat lab5-input | cut -f2 -d!

       4. Create a function called "clean_up" which when invoked
          removes all tmp files in your directory and removes all
          core files from your directory.

       5. Modify your .profile to print out the number of users
          logged on the system every time you log on.

       6. cd to /etc. List all the files in this directory.
          List only the files which are directories.
          List only those  directories which have names rc...
          List only those directories rc0.d to rc3.d


       7. Set up a command called "tim" which displays the time
          when invoked. Use "date" command to get the date and 
          time and pares the line.