Linux Shell Scripting Interview Questions and Answers
Q1. How to skip argument to a script ?
Ans. ./script argument
Example : Script will show filename
Q2. How to use argument in a script ?
Ans. First argument: $1,
Second argument : $2
Example : Script will reproduction report (arg1) to vacation spot (arg2)
./copy.Sh file1.Txt /tmp/
cp $1 $2
Q3. How to calculate number of exceeded arguments ?
Q4. How to get script call inside a script ?
Q5. How to check if previous command run successful ?
Q6. How to get remaining line from a report ?
Ans. Tail -1
Q7. How to get first line from a file ?
Ans. Head -1
Q8. How to get 3rd detail from each line from a report ?
Ans. Awk 'print $3'
Q9. How to get 2nd detail from every line from a document, if first equal FIND
Ans. Awk ' if ($1 == "FIND") print $2'
Q10. How to debug bash script
Ans. Add -xv to #!/bin/bash
Q11. Give an instance a way to write characteristic ?
Ans. Function instance
echo "Hello international!"
Q12. How to add string to string ?
Q13. How to add two integers ?
Remember you want to feature "permit" to line V3=$V1+$V2
then echo $V3 will deliver three
if without allow , then it will be
echo $V3 will provide 1+2
Q14. How to test if record exist on filesystem ?
Ans. If [ -f /var/log/messages ]
echo "File exists"
Q15. Write down syntax for all loops in shell scripting ?
Ans. For loop :
for i in $( ls ); do
echo item: $i
at the same time as loop :
even as [ $COUNTER -lt 10 ]; do
echo The counter is $COUNTER
until loop :
till [ $COUNTER -lt 10 ]; do
echo COUNTER $COUNTER
Q16. What it method via #!/bin/sh or #!/bin/bash at starting of every script ?
Ans. That line tells which shell to apply. #!/bin/bash script to execute using /bin/bash. In case of python script there there could be #!/usr/bin/python
Q17. How to get tenth line from the textual content record ?
Ans. Head -10 reportthe first image inside the bash script document
Q19. What will be the output of command: [ -z "" ] && echo 0 0
Q20. What command "export" do ?
Ans. Makes variable public in subshells
Q21. How to run script in historical past ?
Ans. Upload "&" to the stop of script
Q22. What "chmod 500 script" do ?
Ans. Makes script executable for script owner
Q23. What ">" do ?
Ans. Redirects output move to file or any other stream.
Q24. What distinction among & and &&
Ans. & - we using it when want to place script to history
&& - when we wand to execute command/script if first script become finished correctly
Q25. When we want "if" before [ condition ] ?
Ans. When we want to run numerous commands if circumstance meets.
% video_player "embed_player" overrideable=False, kind='scriptV4', hide_playlist=True, viral_sharing=False, embed_button=False, autoplay=True, hidden_controls=False, loop=False, muted=False, full_width=False, width='1280', height='720', player_id='41686605551', style='' %
Q26. What will be the output of the command: call=John && echo 'My call is $call'
Ans. My name is $call
Q27. Which is the image used for remarks in bash shell scripting ?
Q28. What will be the output of command: echo $new:-variable
Q29. What distinction among ' and " prices ?
Ans. ' - we use it while do no longer want to evaluate variables to the values
" - all variables might be evaluated and its values will be assigned as a substitute.
Q30. How to redirect stdout and stderr streams to log.Txt file from script interior ?
Ans. Add "exec >log.Txt 2>&1" as the first command within the script
Q31. How to get a part of string variable with echo command simplest ?
Ans. Echo $variable:x:y
x - begin position
y - length
variable="My name is Petras, and I am developer."
echo $variable:11:6 # will show Petras
Q32. How to get home_dir with echo command only if string variable="User:123:321:/domestic/dir" is given ?
Ans. Echo $variable#*:*:*:
Q33. How to get “User” from the string above ?
Ans. Echo $variable%:*:*:*
Q34. How to listing customers which UID much less that a hundred (awk) ?
Ans. Awk -F: '$3<one hundred' /and so forth/passwd
Q35. Write the program which counts specific primary groups for users and presentations be counted and organization call only
Ans. Cat /and many others/passwdreducekindwhile examine c g
echo $c; grep :$g: /and many others/organizationcut -d: -f1;done
Q36. How to change general subject separator to ":" in bash shell ?
Q37. How to get variable period ?
Q38. How to print remaining 5 characters of variable ?
Ans. Echo $variable: -five
Q39. What distinction among $variable:-10 and $variable: -10 ?
Ans. $variable:-10 - offers 10 if variable changed into not assigned earlier than
$variable: -10 - gives closing 10 symbols of variable
Q40. How to substitute part of string with echo command handiest ?
Ans. Echo $variable//pattern/alternative
Q41. Which command replaces string to uppercase ?
Ans. Tr '[:lower:]' '[:upper:]'
Q42. How to matter local money owed ?
Ans. Wc -l /etc/passwdcut -d" " -f1
cat /and so on/passwdcount number words in a string with out wc command ?
Ans. Set $string
Q44. Which one is correct "export $variable" or "export variable" ?
Ans. Export variable
Q45. How to listing documents where second letter is a or b ?
Ans.Ls -d ?[ab]*
Q46. How to addbc`
Q47. How to take away all areastr -d " "
Q48. Rewrite the command to print the sentence and changing variable to plural: object="car"; echo "I like $object" ?
Ans. Item="car"; echo "I like $items"
Q49. Write the command with a purpose to print numbers from 0 to a hundred and display each 0.33 (zero 3 6 9 …) ?
Ans. For i in zero..100..3; do echo $i; achieved
for (( i=0; i<=a hundred; i=i+3 )); do echo "Welcome $i times"; executed
Q50. How to print all arguments provided to the script ?
Ans. Echo $*
Q51. What distinction among [ $a == $b ] and [ $a -eq $b ]
Ans. [ $a == $b ] - should be used for string evaluation
[ $a -eq $b ] - should be used for number checks
Q52. What difference among = and ==
Ans. = - we the usage of to assign value to variable
== - we using for string assessment
Q53. Write the command to check if $a more than 12 ?
Ans. [ $a -gt 12 ]
Q54. Write the command to check if $b les or same 12 ?
Ans. [ $b -le 12 ]
Q55. How to check if string starts offevolved with "abc" letters ?
Ans. [[ $string == abc* ]]
Q56. What difference among [[ $string == abc* ]] and [[ $string == "abc*" ]]
Ans. [[ $string == abc* ]] - will test if string starts offevolved with abc letters
[[ $string == "abc*" ]] - will take a look at if string is same exactly to abc*
Q57. How to list usernames which begins^xy" /etc/passwdreduce -d: -f1
Q58) What $! Way in bash ?
Ans. Most recent history command PID
Q59. What $? Approach ?
Ans. Most recent foreground go out fame.
Q60. How to print PID of the cutting-edge shell ?
Ans. Echo $$
Q61. How to get wide variety of handed arguments to the script ?
Ans. Echo $#
Q62. What difference between $* and $@
Ans. $* - offers all exceeded arguments to the script as a single string
$@ - offers all handed arguments to the script as delimited list. Delimiter $IFS
Q63. How to outline array in bash ?
Ans. Array=("Hi" "my" "name" "is")
Q64. How to print the first array element ?
Ans. Echo $array
Q65. How to print all array elements ?
Ans. Echo $array[@]
Q66. How to print all array indexes ?
Ans. Echo $!Array[@]
Q67. How to put off array detail with id 2 ?
Ans. Unset array
Q68. How to add new array detail with identification 333 ?
Q69. How shell script get enter values ?
Ans. A) via parameters
./script param1 param2
b) through read command
read -p "Destination backup Server : " desthost
Q70. How are we able to use "assume" command in a script ?
Ans. /usr/bin/assume << EOD
spawn rsync -ar $line $desthost:$destpath
count on "*?Assword:*"