Operating Systems Management, Lab, 10

Linux Operating System

Lab 10 - For Loop

Instructions:

Use your VI editor to type the scripts, unless otherwise noted. Record output when needed. Do not just write the code and run it. Think about the lines and make sure you understand what the code is doing.

1. Enter vi and create a file called fruits with the code below:

for fruits in apples pears oranges mangoes

do

echo $fruits are fruits

done

2. Save and exit the editor

shift+zz aka ZZ

3. Change the permissions on the file. Give the yourself read, write, and execute and the group and others read only. How did you do this?

chmod 744 fruits

willmcg@willmcg:~$ ls -l fruits

-rwxr--r-- 1 willmcg willmcg 75 Oct 25 14:33 fruits

4. Execute the file fruits. Record the output below:
   

willmcg@willmcg:~$ . fruits

apples are fruits

pears are fruits

oranges are fruits

mangoes are fruits

willmcg@willmcg:~$

5. At your prompt, type vi namelist (This opens your VI Editor and creates a file named: namelist)

for arg in Tom John Eric

do

echo $arg

done

6. Save and exit the editor

7. Make the file executable.

willmcg@willmcg:~$ vi namelist

willmcg@willmcg:~$ ls -l namelist

-rw-rw-r-- 1 willmcg willmcg 44 Oct 25 14:39 namelist

willmcg@willmcg:~$ chmod 744 namelist

willmcg@willmcg:~$ ls -l namelist

-rwxr--r-- 1 willmcg willmcg 44 Oct 25 14:39 namelist

8. Run namelist (use . namelist)

willmcg@willmcg:~$ . namelist

Tom

John

Eric

9. Type the following program: lab10_1

for count in one two three four five

do

echo “In the loop for $count times”

done

10. Run the program and record the output:

willmcg@willmcg:~$ vi lab10_1

willmcg@willmcg:~$ . lab10_1

In the loop for one times

In the loop for two times

In the loop for three times

In the loop for four times

In the loop for five times

11. Is the script above a counter? Why or why not?

it is not a counter because it is using words and not using digits

12. On your own, create a for loop that will give the following output:

The Mets are a Major League Baseball Team

The Yankees are a Major League Baseball Team

The Braves are a Major League Baseball Team

The Astros are a Major League Baseball Team

Write the code below, and circle the keywords:

for team in Mets Yankees Braves Astros

do

echo "The $team are a Major League Baseball Team"

done

13. Write a for loop that will run who, ls, and pwd.

for loop in who w ls pwd

do

$loop

done

you don't need echo it it will just output the same text you wrote, using $ will execute command.

Below is me working thru it. I did need ai asssitance but I understand why now.

for loop in w who ls pwd

do

echo "$loop"

done

for loop in w who ls pwd

do

~~echo `$loop`~~

done

for loop in w who ls pwd ls-l

do

~~$loop~~

done

willmcg@willmcg:~$ vi loop

willmcg@willmcg:~$ . loop

w

who

ls

pwd

willmcg@willmcg:~$ vi loop

[1]+ Stopped vi loop

willmcg@willmcg:~$ . loop

w

who

ls

pwd

willmcg@willmcg:~$ vi loop

willmcg@willmcg:~$ . loop

15:00:39 up 1:28, 1 user, load average: 0.36, 0.36, 0.37

USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT

willmcg tty2 - 13:35 1:13m 0.04s 0.04s /usr/libexec/

1000 seat0 2026-10-25 13:35

1000 tty2 2026-10-25 13:35

Brains Publiclab10_1 lab9_22 snap

Desktop Templateslab10_2 lab9_23 tmp

Documents Videoslab9_11 loop

Downloads customisolab9_19 mlb

Music fruitslab9_20 namelist

Pictures hello_worldlab9_21 protonvpn-stable-release_1.0.8_all.deb

/home/willmcg

willmcg@willmcg:~$

14. What are the for loop keywords?

for in

do

done

15. How do you determine how many times a for loop will run?

how many variables items are in the list after in