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Basic UNIX/Linux commands for Interview Questions – Part 2

April 15, 2010 1 comment

Some basic UNIX/Linux commands (Part-2): [Part-1]
… from college notes !
 

Q36: Display record length of the 1st line of file emp.1st.

Ans: [student@localhost student]$ head -1 emp1.1st |wc –c
41
 

Q37: Display record length of the 1st line of file emp.1st & store result in a variable.

Ans: [student@localhost student]$ p=`head -1 emp1.1st|wc -c`
[student@localhost student]$ echo “$p”
41
 

Q38: Display line no 5 & 7 from emp2.1st

Ans: [student@localhost student]$ head -5 emp2.1st > pp
[student@localhost student]$ tail -1 pp >pp1
[student@localhost student]$ tail -1 emp2.1st >>pp1
[student@localhost student]$ cat pp1
4290|jayant choudhary|executive|production|07/09/50|6000
3564|sudhir agarwal|execute|personnel|06/07/47|7500
 

Q39: Get the year of joining from file emp2.1st of all the emp.

Ans: [student@localhost student]$ cut –d “|” -f 5.7, 5.8 emp2.1st
50
47
58
62
50
55
 

Q40: Create a file shortlist by starting 1st 5 lines of emp1.1st.

Ans: [student@localhost student]$ head -5 emp1.1st | tee shortlist
9876|barun sengupta|director|production|12/03/50|7000
2365|jai sharma|director|personnel|11/05/47|7800
5423|n.k. gupta|chairman|admin|30/08/56|5400
6213|karuna ganguly|g.m|accounts|05/06/62/6300\
4290|jayant choudhary|executive|production|07/09/50|60007
 

Q41: Extract field numbers 2 & 3 from shortlist save as cut1.

Ans: [student@localhost student]$ cut -d”|” -f 2,3 shortlist
barun sengupta|director
jai sharma|director
n.k. gupta|chairman
karuna ganguly|g.m
jayant choudhary|executivem
 

Q42: Extract fields 1,4,5 from shortlist save as cut2.

Ans: [student@localhost student]$ cut -d”|” -f 1,4,5 shortlist >cut2
[student@localhost student]$ cat cut2
9876|production|12/03/50
2365|personnel|11/05/47
5423|admin|30/08/56
6213|accounts|05/06/62/6300\
4290|production|07/09/50
 

Q43: Put all fields of cut1 & cut2 together.

Ans: [student@localhost student]$ paste -d”|” cut1 cut2
a.k. shukla|g.m|9876|production|12/03/50
sumit chakrabarty|d.g.m |2365|personnel|11/05/47
chanchal singhvi | director|5423|admin|30/08/56
s.n dasgupta|manager|6213|accounts|05/06/62/6300\
anil aggarwal|manager|4290|production|07/09/50
 

Q44: Sort on 2nd field of shortlist in two ways.

Ans:
a) [student@localhost student]$ sort -t”|” +1 shortlist
9876|barun sengupta|director|production|12/03/50|7000
2365|jai sharma|director|personnel|11/05/47|7800
4290|jayant choudhary|executive|production|07/09/50|6000
6213|karuna ganguly|g.m|accounts|05/06/62/6300\
5423|n.k. gupta|chairman|admin|30/08/56|5400

b) [student@localhost student]$ sort -t”|” -k2 shortlist
9876|barun sengupta|director|production|12/03/50|7000
2365|jai sharma|director|personnel|11/05/47|7800
4290|jayant choudhary|executive|production|07/09/50|6000
6213|karuna ganguly|g.m|accounts|05/06/62/6300\
 

Q45: Create a sorted output file named sortlist.

Ans: [student@localhost student]$ sort -o sortlist shortlist
[student@localhost student]$ cat shortlist
9876|barun sengupta|director|production|12/03/50|7000
2365|jai sharma|director|personnel|11/05/47|7800
5423|n.k. gupta|chairman|admin|30/08/56|5400
6213|karuna ganguly|g.m|accounts|05/06/62/6300\
4290|jayant choudhary|executive|production|07/09/50|6000
 

Q46: Sort on 3rd field & then by 2nd field of shortlist.

Ans: [student@localhost student]$ sort -t”|” -k 5.7,5.8 shortlist
2365|jai sharma|director|personnel|11/05/47|7800
4290|jayant choudhary|executive|production|07/09/50|6000
9876|barun sengupta|director|production|12/03/50|7000
5423|n.k. gupta|chairman|admin|30/08/56|5400
6213|karuna ganguly|g.m|accounts|05/06/62/6300\
 

Q47: Sort according to year of birth in shortlist.

Ans: [student@localhost student]$ sort -t”|” -k 5.7,5.8 shortlist
2365|jai sharma|director|personnel|11/05/47|7800
4290|jayant choudhary|executive|production|07/09/50|6000
9876|barun sengupta|director|production|12/03/50|7000
5423|n.k. gupta|chairman|admin|30/08/56|5400
6213|karuna ganguly|g.m|accounts|05/06/62/6300\r of birth in shortlist.
 

Q48: Create a file dept.1st.

Ans: [student@localhost student]$ cat >dept.1st
 

Q49: Convert ‘|’ to ‘~’ in emp1.1st.

Ans: [student@localhost student]$ tr ‘|’ ‘~’ <emp1.1st
2233~a.k. shukla~g.m~sales~12/52/52~6000
5678~sumit chakrabarty~d.g.m ~marketing~19/04/43~6000
1006~chanchal singhvi ~ director~sales~03/09/38~6700
1265~s.n dasgupta~manager~sales~12/09/63~5600
2476~anil aggarwal~manager~sales~01/05/59~5000
6521~lalit chowdary~director~marketing~26/09/45~8200
2345~j.b.saxena~g.m~marketing~12/03/45~8000
0110~v.k.agarwal~g.m~marketing~31/12/40~9000
 

Q50: Display frequency of occurance of all the lines.

Ans: [student@localhost student]$ uniq –c
 

Q51: Display lines beginning with 2.

Ans: [student@localhost student]$ grep "^2" emp1.1st
2233|a.k. shukla|g.m|sales|12/52/52|6000
2476|anil aggarwal|manager|sales|01/05/59|5000
2345|j.b.saxena|g.m|marketing|12/03/45|8000
 

Q52: Display lines where salary lie between 7000 & 7999.

Ans: [student@localhost student]$ grep “7…$” emp1.1st
6521|lalit chowdury |director |marketing|26/09/45|8200
2345|j.b.saxena |g.m. |marketing|12/03/45|8000
0110|v.k.agarwal |g.m. |marketing|31/12/40|9000
 

Q53: Remove consecutive occurrences of spaces in emp1.1st.

Ans: [student@localhost student]$ tr –s ‘ ‘ <emp.1st
2233|a.k.shukla|g.m.|sales|12/12/52|6000
5678|sumit chakrobarty|d.g.m|marketing|19/04/43|6000
1006|chanchal singhvi|director|sales|03/09/38|6700
1265|s.n.dasgupta|manager|sales|12/09/68|5600
2476|anil aggarwal|manager|sales|01/05/59|5000
6521|lalit chowdury|director|marketing|26/09/45|8200
2345|j.b.saxena|g.m.|marketing|12/03/45|8000
0110|v.k.agarwal|g.m.|marketing|31/12/40|9000
 

Q54: Convert the contents of emp1.1st to uppercase.

Ans: [student@localhost student]$ sort –f emp1.1st
2233|A.K.SHUKLA |G.M. |SALES |12/12/52|6000
5678|SUMIT CHAKROBARTY |D.G.M |MARKETING|19/04/43|6000
1006|CHANCHAL SINGHVI |DIRECTOR |SALES |03/09/38|6700
1265|S.N.DASGUPTA |MANAGER |SALES |12/09/68|5600
2476|ANIL AGGARWAL |MANAGER |SALES |01/05/59|5000
6521|LALIT CHOWDURY |DIRECTO |MARKETING|26/09/45|8200
2345|J.B.SAXENA |G.M. |MARKETING|12/03/45|8000
0110|V.K.AGARWAL |G.M. |MARKETING|31/12/40|9000
 

Q55: Display lines containing jai sharma with a variable.

Ans: [student@localhost student]$ a=grep ‘jai sharma’ emp.1st
0
 

Q56: Display lines containing jai sharma without a variable.

Ans: [student@localhost student]$ grep ‘jai sharma’ emp.1st
 

Q57: Display lines containing ‘Agarwal’ , ‘agarwal’,& ‘aggarwal’ from emp.1st.

Ans: [student@localhost student]$ grep –e “Agarwal” -e “agarwal” –e
“aggarwal”
2476|anil aggarwal |manager |sales |01/05/59|5000
0110|v.k.agarwal |g.m. |marketing|31/12/40|9000
 

Q58: Display one copy of redundant records of file dept.1st.

Ans: [student@localhost student]$ uniq –d dept.1st
01|accounts |6213
02|admin |5423
03|marketing |6521
04|personnel |2365
05|production|9876
06|sales |1006
 


Basic UNIX/Linux commands for Interview Questions – Part 1

April 11, 2010 1 comment

Some basic UNIX/Linux commands:
… from College notes !
 

Q1. Start UNIX/Linux while logging in remotely to telnet

Ans: [student@localhost student]$ telnet 192.168.0.4
 

Q2. Enter the user name as student and password as student.

Ans: [student@localhost student]$
 

Q3. Display all files starting with a dot and filename more than three characters.

Ans: [student@localhost student]$ ls .???*
 

Q4. Create files chap01,chap02,chap05,chap07,chap*,chap[0-3]

Ans: [student@localhost student]$ cat > chap01
[student@localhost student]$ cat > chap02
[student@localhost student]$ cat > chap05
[student@localhost student]$ cat > chap07
[student@localhost student]$ cat > chap0*
 

Q5. Display all files starting with an alphabet irrespective of the case.

Ans: [student@localhost student]$ ls [a-Za-z]*
 

Q6. Try the command pwd to see the present working directory

Ans: [student@localhost student]$ /home/student
 

Q7. Create files namely abc.txt ,aby.txt ,xdf ,x02,x04,ab4.

Ans: [student@localhost student]$ cat > abc.txt
[student@localhost student]$ cat > aby.txt
[student@localhost student]$ cat > xdf
[student@localhost student]$ cat > x02
[student@localhost student]$ cat > x04
[student@localhost student]$ cat > ab4
 

Q8. Display the files starting with a or t and second character b or x and length of the files should be only 3 characters.

Ans: [student@localhost student]$ ls [a,t][b,x]?
 

Q9. Create directories namely dir1,dir2,dir3

Ans: [student@localhost student]$ mkdir dir1,dir2,dir3.
 

Q10. Create three files in each of the directory.

Ans: [student@localhost student]$ cat > /home/student/dir1/file01
[student@localhost student]$ cat > /home/student/dir2/file02
[student@localhost student]$ cat > /home/student/dir3/file03
 

Q11. Copy all the files from these directories to the current directory.

Ans: [student@localhost student]$
 

Q12. Copy recursively the three directories include , bin, lib from / to directory.

Ans: [student@localhost student]$ cp –R { nitin1,nitin2,nitin3 }
/home/student/kap

 
Q13. Remove the file chap*

Ans: [student@localhost student]$ rm chap*
 

Q14. Display the file contents of file chap[0-3].

Ans: [student@localhost student]$ cat chap[0-3]
 

Q15. Create a file hello.

Ans: [student@localhost student]$ cat > hello
 

Q16. Create a hard link of the file hello name it as hai.

Ans: [student@localhost student]$ ln hello hai
 

Q17. Display the listing of both hello and hai files along either their i-node number.

Ans. [student@localhost student]$ ls –i hello hai
 

Q18. Create the symbolic link of file hello as hellohai

Ans. [student@localhost student]$ ln –s hello hai
 

Q19. Display the listing of both hello and hellohai files along with their i-node number.

Ans. [student@localhost student]$ ls –i hello hellohai
 

Q20. Display the process status of all the processes running on linux.

Ans. [student@localhost student]$ ps
 

Q21. Display the hidden files and also marked them as executable and directory.

Ans. [student@localhost student]$ ls –Fa
 

Q22. Display all the directories, sub- directories and files.

Ans. [student@localhost student]$ls -R
 

Q23. Create a file name in file at 3 to 4 line of text to it.

Ans. [student@localhost student]$cat >infile
 

Q24. Count number of lines, words and characters in the filename infile.

Ans. [student@localhost student]$wc –lwm infile
 

Q25. Count number of words in infile with and without redirection.

Ans. [student@localhost student]$wc –w<infile
 

Q26. In a single command except data as well as display contents of the file infile.

Ans. [student@localhost student]$cat infile –
 

Q27. Display all the files starting with an alphabetic irrespective of the case.

Ans. [student@localhost student]$ls [a-zA-Z]*
 

Q28. Display the number of users logged on.

Ans. [student@localhost student]$who | wc-l
 

Q29. Display the number of files present in the current directory.

Ans. [student@localhost student]$ls –l | wc-l
 

Q30. Count number of bytes of all the .c files individually present in the current directory.

Ans. [student@localhost student]$wc –c *.c
 

Q31. Count total number of bytes of all the .c files present in the current directory.

Ans. [student@localhost student]$wc –c *.c | tail -1 –
 

Q32. Display the statement as there are _ files in the current directory using command substitution.

Ans. [student@localhost student]$echo “There are `ls –l –R | wc –l` files in current dir.”
 

Q33. Try the two statement echo the average pay is $1000
echo ‘the average pay is $1000’
echo “the average pay is $1000”

Ans. [student@localhost student]$echo ‘the average pay is $1000’
the average pay is $1000
echo “the average pay is $1000”
the average pay is 000
 

Q34. Create a shell variable as work and store the present working directory in it and display the same.

Ans. [student@localhost student]$ work=`pwd`
 

Q35. Try the command cat alone without using an argument.

Ans. [student@localhost student]$cat
(With only cat command with no file name it only read standard input.)
 

Check [Part-2] for next set of Questions.