Question

the Unix/Linux commands

1. Enter the “date” command to print the current date and time. Also, try the “cal” command.
2. Enter the command “clear” to clear the screen.
3. Use the command “cat .bash_hisrtory” to view your startup file. Note that each shell has a different startup file, and since we’re using the BASH (Bourne-Again Shell), the startup file is .bash_history. (if you can’t find this file think about one way to display!)
4. Enter the “exit” command to close the terminal window.
5. Enter the command “who” to display all users currently logged onto the system.
6. Enter the commands “whoami” and “who am i” to display your own user information. Note the difference.

Whoami shows my username

7. Enter the “finger” command with your login name to display detailed information about your terminal. (note: if you can’t find finger command, ask your instructor to install it)
8. Change to the “/bin” directory.
9. Display all files (ls –l) from the “/bin” directory.
10. Change to your HOME directory.
11. Use the “cat” command to create a sample text file called “textfile1”. Enter several lines of text of your choice into that file. The output redirection “>” should be used with the cat command “cat > textfile1”.
12. Use the “cat” command to view the file you have just created. Then, use the “wc” command to display statistics information about that file (number of lines, words, and characters).
13. The output redirection can be used with any command. Try the following command which prints all the files in the “/bin” directory into the file output:
14. ls –la /bin > output

15. Use the “cat” command to view the contents of the “output” file. How can you display the contents one page at a time?
16. The output redirection “>” creates a file if it doesn’t exist, and over-writes its contents if the file exists. Try the following command which prints the lists of users into the “output” file we created earlier: who > output
17. Use the “cat” command to display the contents of the “output” file. You’ll notice that the previous contents have been over-written.
18. The output re-direction “>>” can be used to append contents to an existing file. Try this: “date >> output”. You’ll notice that the current date has been appended to the previous contents of the output file.
19. The “touch” command can be used to create an empty file. Try this: “touch myfile”. Check to make sure the file “myfile” has been created.
20. Try the “touch” command on an existing file “touch textfile1” or “touch output”. What is the effect?
21. Create a new file called “memo.txt” with the following information “Hello there, my name is …yourname….”.
22. Append the current date to the end of file “memo.txt”.
23. Invoke the calendar command and redirect its output to the file “memo.txt”.
24. Write a command to display statistics (lines, words, characters) about “memo.txt”.

Answer 1

1. Try the “touch” command on an existing file “touch textfile1” or “touch output”. What is the effect?

when you run touch on an already existing file is that the file's access and modification timestamps are updated to the current time..

for more information on touch command, you can do "man touch".

2. echo “Hello there, my name is …yourname….” > memo.txt

above command will redirect the output of echo command to file having name memo.txt. if file already there, then content will be overwritten.

3. date >> memo.txt

this command will redirect the output of date command which is current date to file memo.txt. it will not overwrite, but at the end of the file it will append that output of date.

4. cal >> memo.txt

same as 3rd one, but redirects the output of calender command.

5. wc -lwc memo.txt

this will print statistics. l for line, w for word, c for character.

6. to display output of file pagewise... use following command...

cat output | more

Hope it helps. Feel free to comment your doubts.