Question

LINUX QUESTIONS (dont have to display output, I will be running these commands myself to check the output)

1. Display the command(s) used to do the following: create an empty file called history by using just a redirection operator. Verify and show. Show/verify all results (i.e., all commands and their corresponding outputs).

2. Wait 1 minute or more and then display the command(s) used to do the following: change the timestamp on the history file you just created. Verify/display the change. Show/verify all results (i.e., all commands and their corresponding outputs).

3. Display the command(s) used to do the following: back up the history file to the file history.bak. Verify/show it was backed up. Show/verify all results (i.e., all commands and their corresponding outputs).

4. Assume you have a subdirectory named datafiles directly under your current working directory (create it if it doesn’t exist). Display the command(s) used to do the following: copy the data1 and data2 files from your current working directory to the datafiles directory. Verify/show that the files are there. Show/verify all results (i.e., all commands and their corresponding outputs).

5. Assume you have 4 files (i.e., create them if they don’t exist): accounts1, accounts2, accounts3, and accounts4 (create them). Display the command(s) used to do the following: write the paste command that combines these files and separates the fields on each line with a “/” character, displaying the results to the screen. Show/verify all results (i.e., all commands and their corresponding outputs).

6. Display the command(s) used to do the following: how would you perform the action in the step above but instead write the results to the file total_accounts? Show/verify all results (i.e., all commands and their corresponding outputs).

7. Assume that you have multiple subdirectories and you want to locate all files that end with the extension “.c” (again, some of them if they don’t exist) in them using one command (including any in subdirectories). Display the command(s) used to do the following: what command can you use to search all of your subdirectories for this file extension? Show/verify all results (i.e., all commands and their corresponding outputs).

8. Create the subdirectory mytest. Display the command(s) used to do the following: copy an existing file into your new subdirectory. Delete the mytest subdirectory and its contents using one command. Show/verify all results (i.e., all commands and their corresponding outputs).

9. You are worried about copying over an existing or newer file in another directory when you use the mv command. What are your options in this situation? Give an example. Explain others. Show/verify all results (i.e., all commands and their corresponding outputs).

10. Display the command(s) used to do the following: what command enables you to find all empty files in your source directory (the source directory is located under your home directory and was created in a previous homework assignment ... create it if it doesn’t exist)? Show/verify all results (i.e., all commands and their corresponding outputs).

11. Display the command(s) used to do the following: how can you find all files in your home directory that were modified in the last 7 days? Show/verify all results (i.e., all commands and their corresponding outputs).

12. Display the command(s) used to do the following: how can you put the contents of each line of the product1 file side by side with the contents of the product2 file but with only a dash in-between instead of a tab? Show/verify all results (i.e., all commands and their corresponding outputs).

13. Display the command(s) used to do the following: how can you use a command you have learned in this chapter to list the names of all users on your system? (Hint: Find out the name of the file in which user information is stored.) Show/verify all results (i.e., all commands and their corresponding outputs).

14. Type who and press “Enter” to view a list of logged-in users along with other information. Display the command(s) used to do the following: now use the who command (which you learned about in Chapter 1) with a command you learned in this chapter to view who is logged in but to suppress all other information that normally accompanies the who command (see pipe (|) symbol). Show/verify all results (i.e., all commands and their corresponding outputs).

15. Display the command(s) used to do the following: use a command to find the instances in which the word “host” is used in the /etc directory in file names. Show/verify all results (i.e., all commands and their corresponding outputs).

16. Display the command(s) used to do the following: use a command to find out which lines (i.e., output line numbers) in the my_list file contain the word “Foot” (create this file if it doesn’t exist). Show/verify all results (i.e., all commands and their corresponding outputs).

17. Display the command(s) used to do the following: create a file called trees, containing the following individual lines using vi:

Oak tree

Pine tree

Spruce tree

Cottonwood

Maple tree

Use the vi editor to create a file called more_trees and copy in the contents of the trees file (if the first line is blank, delete it). Next, add the following trees at the end of the list.

Redwood

Willow tree

Use a command to compare the trees and more_trees files and that outputs the differences in columns.

Use a command to compare the trees and more_trees files and show the differences in terms of individual lines that differ.

Determine the number of bytes in both the trees and more_trees files using a 1-line command.

Use a command to replace the word “tree” with “plant” in the more_trees file and display the output to the screen.

Show/verify all results (i.e., all commands and their corresponding outputs).

18. Display the command(s) used to do the following: create a new file, CD_list, and enter these lines in the file:

country:1000:210

rock:1001:380

classical:1002:52

alternative:1003:122

light rock:1004:151

light rock:1004:151

celtic:1005:44

jazz:1006:62

soundtracks:1007:32

soundtracks:1007:32

Use the sed command and a script file to add these lines to the end of the CD_list file:

hard rock:1008:70

misc:1009:22

Use a command to find the duplicate lines (records) in the CD_list file.

Use the uniq command to remove the duplicate lines in the CD_list file, placing the corrected information in a file called CD_list_new.

        Show/verify all results (i.e., all commands and their corresponding outputs).

19. Display the command(s) used to do the following: in the CD_list_new file, replace the word “misc” with “other,” save the changes in the file CD_list_replace, and then compare the contents of the CD_list file with the CD_list_replace file to ensure your changes are implemented.

Use the grep command to find all of the lines that contain the word “celtic” in the CD_list_new file.

Show/verify all results (i.e., all commands and their corresponding outputs).

20. Display the command(s) used to do the following: use a command to make all letters uppercase in the CD_list_new file and save the output to a file called CD_list_uppercase.

Use the sed command on the CD_list_new file to replace the words “light rock” with “easy listening” and the word “alternative” with “experimental.”

       Show/verify all results (i.e., all commands and their corresponding outputs).

Answer 1

Display the command(s) used to do the following: create an empty file called history by using just a redirection operator. Verify and show. Show/verify all results (i.e., all commands and their corresponding outputs).

touch history

Wait 1 minute or more and then display the command(s) used to do the following: change the timestamp on the history file you just created. Verify/display the change. Show/verify all results (i.e., all commands and their corresponding outputs).

touch -t 201010161000 history

Display the command(s) used to do the following: back up the history file to the file history.bak. Verify/show it was backed up. Show/verify all results (i.e., all commands and their corresponding outputs).

cp history history.bak

Assume you have a subdirectory named datafiles directly under your current working directory (create it if it doesn’t exist). Display the command(s) used to do the following: copy the data1 and data2 files from your current working directory to the datafiles directory. Verify/show that the files are there. Show/verify all results (i.e., all commands and their corresponding outputs).

mkdir datafiles
cp data1 data2 datafiles/

Assume you have 4 files (i.e., create them if they don’t exist): accounts1, accounts2, accounts3, and accounts4 (create them). Display the command(s) used to do the following: write the paste command that combines these files and separates the fields on each line with a “/” character, displaying the results to the screen. Show/verify all results (i.e., all commands and their corresponding outputs).

touch accounts{1..4}
cat accounts1 accounts2 accounts3 accounts4 > merged

We are allowed to do only 4 exercise out of any given.

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