This document contains questions and answers about file processing commands in UNIX/Linux. It includes questions about commands like cut, grep, sort, uniq, ls and how to view specific fields of data from files, search for strings within files, sort and filter the contents of files.

1. UOP POS 433 Week 4 File Processing Commands
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1. How do you know how many number of users
currently logged into the system? (Not considering
if any user is logged more than one time) (1)
A. who | uniq | sort | wc -l
B. who | cut -d' ' –f1 | uniq | wc -l
C. who | sort | uniq | wc -l
D. who | cut -d' ' –f1 | sort -u | wc -l
E. who | cut -d' ' –f1 | uniq -d | wc -l
Ans:
2. Create a file “employees.txt” using vi editor or
pico.
(The file will have 6 fields, ID, Name, Designation,
Dept, D.O.B, Salary separated by pipe)
Enter these lines in the file and save it.
2133|charles smith |Manager|sales|12/12/56|
90000
9576|Rob Thomson|director |production|

2. 03/12/50|130000
5778|David Blake |General Manager|marketing |
04/19/43| 85000
2765|Rick Martin|director|personnel |05/11/47|
120000
(Use cut command for the following questions A,B)
(in each one mark, ½ is for the command and ½
for the output)
A. Display the person's name, his designation and
salary in the above file.
Show the command and output
Ans:
B: Display first 20 characters on each line in the
above file.
Show the command and output
Ans:
3. How do you display the hour and minute from
date command using cut utility (1)
Show the command and output
( ½ is for the command and ½ for the output)
Ans:
4. What is the difference between the following
commands? (1)
$ who | grep 'mary'

3. and
$ who | grep '^mary'
Ans:
5. We know that all user information is stored
in /etc/passwd where fields are delimited by a
colon. Display only their userids using cut
command. (userid is the first field in /etc/passwd
file) Show only top 10 userids. (1)
Show the command and output
( ½ is for the command and ½ for the output)
Ans:
6. Create the following four files chapter1,
chapter2, chapter3, chapter4 in your current
directory and enter the following text:
Chapter1 :
This is the first line in this file
This chapter deals with the basic information of a
UNIX system.
Chapter2 :
This is the first line in this file
This chapter deals with Unix System info and shell
introduction.
Chapter3 :
This is the first line in this File System
This chapter deals with various Unix Systems.

4. Chapter4 :
This is the first line in this file
This chapter deals with kernel system.
The question is to search for a string "System" or
"system" in the above files. Use wild cards in both
pattern and file searching. (1)
Show the command and output
( ½ is for the command and ½ for the output)
Ans:
7. Show these commands and output:
A. Redirect man pages of ‘find’ command to a file
called, find_manpages in /tmp directory.
B. Display lines not having the word “version” in
the above file.(1)
(½ is for the command and ½ for the output)
Ans:
8. Which command of the following is correct ?
(Some may work but does not make sense). (1)
a. cat file file> file3 | wc -l
b. cut -d ":" filename
c. ls -l | grepunixmyfile
d. head filename | tail
e. find name "myfile.txt" -print
9. We know that ls -l command shows all the files
in the current directory. How do you display only

5. the directories, not files in the current directory.
(You have to use ls command, but not find
command) (1)
Ans:
10. How do you set only read permissions to user,
group and others in octal mode for a file
"myfile.txt" ? (1)
Ans:
11. You observed that some of your group
members are fiddling with your file "myfile" and
you wanted to remove the read permission to your
group. How do you do? (1)
Ans:
12. Here is the long listing of a file.
-rw-rw-rw- 2 Y435678 odms 22 Sep 02 12:03
myfile.txt
Is the above a file or a directory? To which group
does it belong? (1)
Regular file, Y435678
file, Y435678
file, odms
directory, odms

6. directory, Y435678
Ans :
13. Here is another long listing of a file. (1)
-rw-r----- 1 Y435678 odms 20 Sep 02 17:03 file.txt.
What are the owner permissions?
read, execute
read, write
write, execute
all since s/he is the owner
Ans:
14. The file users_data has the following contents :
(1)
Tom Smith 7.00 15 105.00
Rob Sheryl 8.00 20 160.00
Ken Bradman 7.00 13 91.00
Peter Smith 6.00 15 90.00
Dennis Smith 8.00 13 104.00
Tom Dave 9.00 12 108.00
How do you sort the above file and redirect the
output to another file called sortedusers
Ans :
15. How do you list only duplicate lines in a file

7. "myfile" (1)
Ans :