Hi there. I am working on a school assignment and it's my last assignment. Unfortunately, I have been missing 4 lecture sessions. Anyways, I am trying to get started but I'm already stuck on the first part where I am supposed to get lines 100-110.
Here are the descriptions to the assignment:
CS140U Lab 7
Practice input/output redirection and piping
Practice writing simple scripts
Practice archiving files using tar
Build a user reference data file with the usernames and full names by extracting the necessary information from the /etc/passwd file.
Sort the /etc/passwd and get line 100-110 of that file. Use the cut command to extract the username from /etc/passwd. Save the result file as ids.
Create another file called names which contain full names of line 100-110 of sorted /etc/passwd in a similar way.
Use the paste command to combine the two files, ids and names, together side-by-side as shown below, redirect the output to a file called users.ref. For ease of processing, separate the two fields with a space. If there is any ‘,’ in the file, use an editor to get rid of them. The final version of users.ref should look like the following format:
sally.black Sally Black
jane.smith Jane Smith
lily.brown Lily Brown
Before you continue with Part II, it is a good idea to save a copy of users.ref. You will know why when you accidentally erase the contents of the data file.
For the following steps, write shell programs that use command line arguments as input to the shell program. Do not prompt the user for input from the keyboard!
Note: Most of these shell programs need to be only 1 or 2 lines long.
Write a shell program called list to display all the usernames and full names in the users.ref file. The information should be displayed in alphabetical order by student's last name (not by username). Save the list shell program in your lab7 directory.
Write a shell program called find to locate an existing record in users.ref and display the student's username and full name on the screen. The search should not be case sensitive. This shell program should allow the user to specify either a student's username or their full name. Save the find shell program in the lab7 directory.
$ find "lily.brown" or $ find 'Lily Brown'
Did you encounter any problems in the previous step? If so, what were they and how did you resolve them? Include a note describing the problems and solutions in a file called lab7.notes.
Write a shell program called remove which deletes a student's entry from your users.ref file. Similar to find, the user should be able to specify the student to be removed by their username or their full name. Save the remove shell program in lab7. (hint: grep has an option "-v". Go check it out!)
Write a shell program called add to add a new username and full student's name to your users.ref file. Your program should be used in the following manner (hint: echo hello >> file):
$ add woody.brown 'Woody Brown'
Verify correct operation of your shell programs. Use the script command to record your test results. Type script at the command line. This will start a new shell that "captures" all input and output and records it in a file named typescript in your current directory.
Execute the pwd command.
Execute the ls command.
Execute your list command.
Execute your find command (or whatever you named it) twice. (Once to locate a student by their username and a second time to locate them by their full name.)
Use your remove shell program twice: once to remove a student using their username, another removing them by their full name.
Use your add shell program to add an entry to the file
Execute your list command a second time.
Type exit (or ctrl-d) to exit the script shell. The input and output were written to a file called typescript. Change the name of this file to script1 and save it in the lab7 directory.
Use the "tar" (tape archive) command to wrap all the files into a single file, and then send only that file to lliang via mailx . The files to wrap with the tape archive are your final versions of:
Copy all of the final versions of your shell programs into your lab7 directory. Then use the following tar command to create your archive:
tar –cvf lab7.tar lab7
Be sure to include the latest version of each of your files! Move lab7.tar to a temp directory. Try the following command to confirm you have included everything
tar –xvf lab7.tar
Use mailx to e-mail the archive file lab7.tar to your instructor at lliang to complete the Lab 7 assignment. Make the subject of your message “Last Name, First Name lab7 submission” when mailing your lab to the instructor. Here is the command line you can use: