How to re-run the case statement if the input is invalid? [duplicate]

Clash Royale CLAN TAG#URR8PPP

up vote
6
down vote

favorite

This question already has an answer here:

• 
  How to repeat prompt to user in a shell script?
  
  2 answers
  
  

I have the following code in the middle of a script to confirm whether we want to resume the script or not.

read -r -p "Would you like to continue [Y/N] : " i
case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 ;;
esac

I would like to know is there any way to know is there any way to recall the switch-case if the input option is invalid?

linux bash shell-script case

share|improve this question

edited Sep 3 at 17:18

Kusalananda

105k14209326

asked Sep 3 at 16:27

user308897

marked as duplicate by Jeff Schaller, G-Man, Thomas, SivaPrasath, Romeo Ninov Sep 4 at 11:43

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  You need to rerun the switch case if the input is other than Y and N, am i right?
  – SivaPrasath
  Sep 3 at 16:30
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Sivaprasath, Yes
  – user308897
  Sep 3 at 16:30
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Use functions from the main level of your script so that you can control flow more easily.
  – slm♦
  Sep 3 at 16:31
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  If it's bash, you can use select statement - that one doesn't exit until you have valid input, IIRC
  – Sergiy Kolodyazhnyy
  Sep 3 at 18:47
  

  
  
  
  

add a comment | 

up vote
6
down vote

favorite

This question already has an answer here:

• 
  How to repeat prompt to user in a shell script?
  
  2 answers
  
  

I have the following code in the middle of a script to confirm whether we want to resume the script or not.

read -r -p "Would you like to continue [Y/N] : " i
case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 ;;
esac

I would like to know is there any way to know is there any way to recall the switch-case if the input option is invalid?

linux bash shell-script case

share|improve this question

edited Sep 3 at 17:18

Kusalananda

105k14209326

asked Sep 3 at 16:27

user308897

marked as duplicate by Jeff Schaller, G-Man, Thomas, SivaPrasath, Romeo Ninov Sep 4 at 11:43

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  You need to rerun the switch case if the input is other than Y and N, am i right?
  – SivaPrasath
  Sep 3 at 16:30
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Sivaprasath, Yes
  – user308897
  Sep 3 at 16:30
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Use functions from the main level of your script so that you can control flow more easily.
  – slm♦
  Sep 3 at 16:31
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  If it's bash, you can use select statement - that one doesn't exit until you have valid input, IIRC
  – Sergiy Kolodyazhnyy
  Sep 3 at 18:47
  

  
  
  
  

add a comment | 

up vote
6
down vote

favorite

up vote
6
down vote

favorite

This question already has an answer here:

• 
  How to repeat prompt to user in a shell script?
  
  2 answers
  
  

I have the following code in the middle of a script to confirm whether we want to resume the script or not.

read -r -p "Would you like to continue [Y/N] : " i
case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 ;;
esac

I would like to know is there any way to know is there any way to recall the switch-case if the input option is invalid?

linux bash shell-script case

share|improve this question

edited Sep 3 at 17:18

Kusalananda

105k14209326

asked Sep 3 at 16:27

user308897

This question already has an answer here:

• 
  How to repeat prompt to user in a shell script?
  
  2 answers
  
  

I have the following code in the middle of a script to confirm whether we want to resume the script or not.

read -r -p "Would you like to continue [Y/N] : " i
case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 ;;
esac

I would like to know is there any way to know is there any way to recall the switch-case if the input option is invalid?

This question already has an answer here:

• 
  How to repeat prompt to user in a shell script?
  
  2 answers
  
  

linux bash shell-script case

share|improve this question

edited Sep 3 at 17:18

Kusalananda

105k14209326

asked Sep 3 at 16:27

user308897

share|improve this question

share|improve this question

edited Sep 3 at 17:18

Kusalananda

105k14209326

edited Sep 3 at 17:18

Kusalananda

105k14209326

edited Sep 3 at 17:18

Kusalananda

105k14209326

105k14209326

asked Sep 3 at 16:27

user308897

asked Sep 3 at 16:27

user308897

asked Sep 3 at 16:27

user308897

marked as duplicate by Jeff Schaller, G-Man, Thomas, SivaPrasath, Romeo Ninov Sep 4 at 11:43

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

marked as duplicate by Jeff Schaller, G-Man, Thomas, SivaPrasath, Romeo Ninov Sep 4 at 11:43

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  You need to rerun the switch case if the input is other than Y and N, am i right?
  – SivaPrasath
  Sep 3 at 16:30
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Sivaprasath, Yes
  – user308897
  Sep 3 at 16:30
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Use functions from the main level of your script so that you can control flow more easily.
  – slm♦
  Sep 3 at 16:31
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  If it's bash, you can use select statement - that one doesn't exit until you have valid input, IIRC
  – Sergiy Kolodyazhnyy
  Sep 3 at 18:47
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  You need to rerun the switch case if the input is other than Y and N, am i right?
  – SivaPrasath
  Sep 3 at 16:30
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Sivaprasath, Yes
  – user308897
  Sep 3 at 16:30
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Use functions from the main level of your script so that you can control flow more easily.
  – slm♦
  Sep 3 at 16:31
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  If it's bash, you can use select statement - that one doesn't exit until you have valid input, IIRC
  – Sergiy Kolodyazhnyy
  Sep 3 at 18:47
  

  
  
  
  

1

1

You need to rerun the switch case if the input is other than Y and N, am i right?
– SivaPrasath
Sep 3 at 16:30

You need to rerun the switch case if the input is other than Y and N, am i right?
– SivaPrasath
Sep 3 at 16:30

Sivaprasath, Yes
– user308897
Sep 3 at 16:30

Sivaprasath, Yes
– user308897
Sep 3 at 16:30

Use functions from the main level of your script so that you can control flow more easily.
– slm♦
Sep 3 at 16:31

Use functions from the main level of your script so that you can control flow more easily.
– slm♦
Sep 3 at 16:31

1

1

If it's bash, you can use select statement - that one doesn't exit until you have valid input, IIRC
– Sergiy Kolodyazhnyy
Sep 3 at 18:47

If it's bash, you can use select statement - that one doesn't exit until you have valid input, IIRC
– Sergiy Kolodyazhnyy
Sep 3 at 18:47

add a comment | 

4 Answers
4

active

oldest

votes

up vote
12
down vote

Do your input in a loop. Exit the loop with break (or exit as the case may be) if you get a valid response from the user.

while true; do
 read -p 'Continue? yes/no: ' input
 case $input in
 [yY]*)
 echo 'Continuing'
 break
 ;;
 [nN]*)
 echo 'Ok, exiting'
 exit 1
 ;;
 *)
 echo 'Invalid input' >&2
 esac
done

As a utility function:

ask_continue () 
 while true; do
 read -p 'Continue? yes/no: ' input 
 case $input in
 [yY]*)
 echo 'Continuing'
 break
 ;;
 [nN]*)
 echo 'Ok, exiting'
 exit 1
 ;;
 *)
 echo 'Invalid input' >&2
 esac
 done

A variation of the utility function that allows exiting through EOF (e.g. pressing Ctrl+D):

ask_continue () 
 while read -p 'Continue? yes/no: ' input; do 
 case $input in
 [yY]*)
 echo 'Continuing'
 return
 ;;
 [nN]*)
 break
 ;;
 *)
 echo 'Invalid input' >&2
 esac
 done

 echo 'Ok, exiting'
 exit 1

Here, there are three ways out of the loop:

1. The user enters "yes", in which case the function returns.


2. The user enters "no", in which case the we break out of the loop and execute exit 1.


3. The read fails due to something like encountering an end-of-input or some other error, in which case the exit 1 is executed.

share|improve this answer

edited Sep 4 at 5:58

answered Sep 3 at 16:41

Kusalananda

105k14209326

• 
  
  
  

  
  

  
  
  
  
  
  

  
  You may also want to exit the script upon empty input (EOF).
  – Stéphane Chazelas
  Sep 3 at 22:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @StéphaneChazelas Yes, definitely. I'll update in the morning. Thanks.
  – Kusalananda
  Sep 3 at 22:45
  

  
  
  
  

add a comment | 

up vote
6
down vote

Why not just repeating the read?

unset i
while [[ ! "$i" =~ ^[yYnN]$ ]]; do read -r -p "Would you like to continue [Y/N] : " i; done

share|improve this answer

answered Sep 3 at 16:46

RudiC

1,1616

add a comment | 

up vote
3
down vote

You can do by keeping switch case inside a function.

function testCase ()

 read -r -p "Would you like to continue [Y/N] : " i
 case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 testCase
 ;;
 esac

testCase

If the input is invalid it will recall the function until it gets a valid input.

share|improve this answer

answered Sep 3 at 16:33

SivaPrasath

1

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  Or until you run into a resource restriction or a maximum recursion depth limit.
  – Kusalananda
  Sep 3 at 16:35
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Thanks a lot it works!!
  – user308897
  Sep 3 at 16:42
  

  
  
  
  


• 
  
  
  

  
  8
  

  
  
  
  
  
  

  
  I wouldn't count on the shell being able to optimize the tail recursion, and given the usual procedural nature of shell scripts, I'd really suggest writing that loop out.
  – ilkkachu
  Sep 3 at 18:33
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  @Kusalananda If the user gives an incorrect answer to a simple yes/no question so many times you hit the recursion limit, he deserves to have the script crash.
  – Barmar
  Sep 3 at 21:45
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @Barmar A programmer should expect that the user will input anything, whether it's an incorrect answer enough times to hit a recursion limit, or eight gigabytes of null and control codes. Failing on a corner case like this is indicative of bad programming.
  – forest
  Sep 4 at 0:47
  
  

  
  
  
  

add a comment | 

up vote
1
down vote

until [ "$i" = "0" ]
do
read -r -p "Would you like to continue [Y/N] : " i
case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 ;;
esac
done

share|improve this answer

answered Sep 3 at 18:21

GAD3R

22.7k154895

add a comment | 

4 Answers
4

active

oldest

votes

4 Answers
4

active

oldest

votes

active

oldest

votes

active

oldest

votes

up vote
12
down vote

Do your input in a loop. Exit the loop with break (or exit as the case may be) if you get a valid response from the user.

while true; do
 read -p 'Continue? yes/no: ' input
 case $input in
 [yY]*)
 echo 'Continuing'
 break
 ;;
 [nN]*)
 echo 'Ok, exiting'
 exit 1
 ;;
 *)
 echo 'Invalid input' >&2
 esac
done

As a utility function:

ask_continue () 
 while true; do
 read -p 'Continue? yes/no: ' input 
 case $input in
 [yY]*)
 echo 'Continuing'
 break
 ;;
 [nN]*)
 echo 'Ok, exiting'
 exit 1
 ;;
 *)
 echo 'Invalid input' >&2
 esac
 done

A variation of the utility function that allows exiting through EOF (e.g. pressing Ctrl+D):

ask_continue () 
 while read -p 'Continue? yes/no: ' input; do 
 case $input in
 [yY]*)
 echo 'Continuing'
 return
 ;;
 [nN]*)
 break
 ;;
 *)
 echo 'Invalid input' >&2
 esac
 done

 echo 'Ok, exiting'
 exit 1

Here, there are three ways out of the loop:

1. The user enters "yes", in which case the function returns.


2. The user enters "no", in which case the we break out of the loop and execute exit 1.


3. The read fails due to something like encountering an end-of-input or some other error, in which case the exit 1 is executed.

share|improve this answer

edited Sep 4 at 5:58

answered Sep 3 at 16:41

Kusalananda

105k14209326

• 
  
  
  

  
  

  
  
  
  
  
  

  
  You may also want to exit the script upon empty input (EOF).
  – Stéphane Chazelas
  Sep 3 at 22:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @StéphaneChazelas Yes, definitely. I'll update in the morning. Thanks.
  – Kusalananda
  Sep 3 at 22:45
  

  
  
  
  

add a comment | 

up vote
12
down vote

Do your input in a loop. Exit the loop with break (or exit as the case may be) if you get a valid response from the user.

while true; do
 read -p 'Continue? yes/no: ' input
 case $input in
 [yY]*)
 echo 'Continuing'
 break
 ;;
 [nN]*)
 echo 'Ok, exiting'
 exit 1
 ;;
 *)
 echo 'Invalid input' >&2
 esac
done

As a utility function:

ask_continue () 
 while true; do
 read -p 'Continue? yes/no: ' input 
 case $input in
 [yY]*)
 echo 'Continuing'
 break
 ;;
 [nN]*)
 echo 'Ok, exiting'
 exit 1
 ;;
 *)
 echo 'Invalid input' >&2
 esac
 done

A variation of the utility function that allows exiting through EOF (e.g. pressing Ctrl+D):

ask_continue () 
 while read -p 'Continue? yes/no: ' input; do 
 case $input in
 [yY]*)
 echo 'Continuing'
 return
 ;;
 [nN]*)
 break
 ;;
 *)
 echo 'Invalid input' >&2
 esac
 done

 echo 'Ok, exiting'
 exit 1

Here, there are three ways out of the loop:

1. The user enters "yes", in which case the function returns.


2. The user enters "no", in which case the we break out of the loop and execute exit 1.


3. The read fails due to something like encountering an end-of-input or some other error, in which case the exit 1 is executed.

share|improve this answer

edited Sep 4 at 5:58

answered Sep 3 at 16:41

Kusalananda

105k14209326

• 
  
  
  

  
  

  
  
  
  
  
  

  
  You may also want to exit the script upon empty input (EOF).
  – Stéphane Chazelas
  Sep 3 at 22:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @StéphaneChazelas Yes, definitely. I'll update in the morning. Thanks.
  – Kusalananda
  Sep 3 at 22:45
  

  
  
  
  

add a comment | 

up vote
12
down vote

up vote
12
down vote

Do your input in a loop. Exit the loop with break (or exit as the case may be) if you get a valid response from the user.

while true; do
 read -p 'Continue? yes/no: ' input
 case $input in
 [yY]*)
 echo 'Continuing'
 break
 ;;
 [nN]*)
 echo 'Ok, exiting'
 exit 1
 ;;
 *)
 echo 'Invalid input' >&2
 esac
done

As a utility function:

ask_continue () 
 while true; do
 read -p 'Continue? yes/no: ' input 
 case $input in
 [yY]*)
 echo 'Continuing'
 break
 ;;
 [nN]*)
 echo 'Ok, exiting'
 exit 1
 ;;
 *)
 echo 'Invalid input' >&2
 esac
 done

A variation of the utility function that allows exiting through EOF (e.g. pressing Ctrl+D):

ask_continue () 
 while read -p 'Continue? yes/no: ' input; do 
 case $input in
 [yY]*)
 echo 'Continuing'
 return
 ;;
 [nN]*)
 break
 ;;
 *)
 echo 'Invalid input' >&2
 esac
 done

 echo 'Ok, exiting'
 exit 1

Here, there are three ways out of the loop:

1. The user enters "yes", in which case the function returns.


2. The user enters "no", in which case the we break out of the loop and execute exit 1.


3. The read fails due to something like encountering an end-of-input or some other error, in which case the exit 1 is executed.

share|improve this answer

edited Sep 4 at 5:58

answered Sep 3 at 16:41

Kusalananda

105k14209326

Do your input in a loop. Exit the loop with break (or exit as the case may be) if you get a valid response from the user.

while true; do
 read -p 'Continue? yes/no: ' input
 case $input in
 [yY]*)
 echo 'Continuing'
 break
 ;;
 [nN]*)
 echo 'Ok, exiting'
 exit 1
 ;;
 *)
 echo 'Invalid input' >&2
 esac
done

As a utility function:

ask_continue () 
 while true; do
 read -p 'Continue? yes/no: ' input 
 case $input in
 [yY]*)
 echo 'Continuing'
 break
 ;;
 [nN]*)
 echo 'Ok, exiting'
 exit 1
 ;;
 *)
 echo 'Invalid input' >&2
 esac
 done

A variation of the utility function that allows exiting through EOF (e.g. pressing Ctrl+D):

ask_continue () 
 while read -p 'Continue? yes/no: ' input; do 
 case $input in
 [yY]*)
 echo 'Continuing'
 return
 ;;
 [nN]*)
 break
 ;;
 *)
 echo 'Invalid input' >&2
 esac
 done

 echo 'Ok, exiting'
 exit 1

Here, there are three ways out of the loop:

1. The user enters "yes", in which case the function returns.


2. The user enters "no", in which case the we break out of the loop and execute exit 1.


3. The read fails due to something like encountering an end-of-input or some other error, in which case the exit 1 is executed.

share|improve this answer

edited Sep 4 at 5:58

answered Sep 3 at 16:41

Kusalananda

105k14209326

share|improve this answer

share|improve this answer

edited Sep 4 at 5:58

edited Sep 4 at 5:58

edited Sep 4 at 5:58

answered Sep 3 at 16:41

Kusalananda

105k14209326

answered Sep 3 at 16:41

Kusalananda

105k14209326

answered Sep 3 at 16:41

Kusalananda

105k14209326

105k14209326

• 
  
  
  

  
  

  
  
  
  
  
  

  
  You may also want to exit the script upon empty input (EOF).
  – Stéphane Chazelas
  Sep 3 at 22:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @StéphaneChazelas Yes, definitely. I'll update in the morning. Thanks.
  – Kusalananda
  Sep 3 at 22:45
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  

  
  
  
  
  
  

  
  You may also want to exit the script upon empty input (EOF).
  – Stéphane Chazelas
  Sep 3 at 22:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @StéphaneChazelas Yes, definitely. I'll update in the morning. Thanks.
  – Kusalananda
  Sep 3 at 22:45
  

  
  
  
  

You may also want to exit the script upon empty input (EOF).
– Stéphane Chazelas
Sep 3 at 22:14

You may also want to exit the script upon empty input (EOF).
– Stéphane Chazelas
Sep 3 at 22:14

@StéphaneChazelas Yes, definitely. I'll update in the morning. Thanks.
– Kusalananda
Sep 3 at 22:45

@StéphaneChazelas Yes, definitely. I'll update in the morning. Thanks.
– Kusalananda
Sep 3 at 22:45

add a comment | 

up vote
6
down vote

Why not just repeating the read?

unset i
while [[ ! "$i" =~ ^[yYnN]$ ]]; do read -r -p "Would you like to continue [Y/N] : " i; done

share|improve this answer

answered Sep 3 at 16:46

RudiC

1,1616

add a comment | 

up vote
6
down vote

Why not just repeating the read?

unset i
while [[ ! "$i" =~ ^[yYnN]$ ]]; do read -r -p "Would you like to continue [Y/N] : " i; done

share|improve this answer

answered Sep 3 at 16:46

RudiC

1,1616

add a comment | 

up vote
6
down vote

up vote
6
down vote

Why not just repeating the read?

unset i
while [[ ! "$i" =~ ^[yYnN]$ ]]; do read -r -p "Would you like to continue [Y/N] : " i; done

share|improve this answer

answered Sep 3 at 16:46

RudiC

1,1616

Why not just repeating the read?

unset i
while [[ ! "$i" =~ ^[yYnN]$ ]]; do read -r -p "Would you like to continue [Y/N] : " i; done

share|improve this answer

answered Sep 3 at 16:46

RudiC

1,1616

share|improve this answer

share|improve this answer

answered Sep 3 at 16:46

RudiC

1,1616

answered Sep 3 at 16:46

RudiC

1,1616

answered Sep 3 at 16:46

RudiC

1,1616

1,1616

add a comment | 

add a comment | 

up vote
3
down vote

You can do by keeping switch case inside a function.

function testCase ()

 read -r -p "Would you like to continue [Y/N] : " i
 case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 testCase
 ;;
 esac

testCase

If the input is invalid it will recall the function until it gets a valid input.

share|improve this answer

answered Sep 3 at 16:33

SivaPrasath

1

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  Or until you run into a resource restriction or a maximum recursion depth limit.
  – Kusalananda
  Sep 3 at 16:35
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Thanks a lot it works!!
  – user308897
  Sep 3 at 16:42
  

  
  
  
  


• 
  
  
  

  
  8
  

  
  
  
  
  
  

  
  I wouldn't count on the shell being able to optimize the tail recursion, and given the usual procedural nature of shell scripts, I'd really suggest writing that loop out.
  – ilkkachu
  Sep 3 at 18:33
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  @Kusalananda If the user gives an incorrect answer to a simple yes/no question so many times you hit the recursion limit, he deserves to have the script crash.
  – Barmar
  Sep 3 at 21:45
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @Barmar A programmer should expect that the user will input anything, whether it's an incorrect answer enough times to hit a recursion limit, or eight gigabytes of null and control codes. Failing on a corner case like this is indicative of bad programming.
  – forest
  Sep 4 at 0:47
  
  

  
  
  
  

add a comment | 

up vote
3
down vote

You can do by keeping switch case inside a function.

function testCase ()

 read -r -p "Would you like to continue [Y/N] : " i
 case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 testCase
 ;;
 esac

testCase

If the input is invalid it will recall the function until it gets a valid input.

share|improve this answer

answered Sep 3 at 16:33

SivaPrasath

1

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  Or until you run into a resource restriction or a maximum recursion depth limit.
  – Kusalananda
  Sep 3 at 16:35
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Thanks a lot it works!!
  – user308897
  Sep 3 at 16:42
  

  
  
  
  


• 
  
  
  

  
  8
  

  
  
  
  
  
  

  
  I wouldn't count on the shell being able to optimize the tail recursion, and given the usual procedural nature of shell scripts, I'd really suggest writing that loop out.
  – ilkkachu
  Sep 3 at 18:33
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  @Kusalananda If the user gives an incorrect answer to a simple yes/no question so many times you hit the recursion limit, he deserves to have the script crash.
  – Barmar
  Sep 3 at 21:45
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @Barmar A programmer should expect that the user will input anything, whether it's an incorrect answer enough times to hit a recursion limit, or eight gigabytes of null and control codes. Failing on a corner case like this is indicative of bad programming.
  – forest
  Sep 4 at 0:47
  
  

  
  
  
  

add a comment | 

up vote
3
down vote

up vote
3
down vote

You can do by keeping switch case inside a function.

function testCase ()

 read -r -p "Would you like to continue [Y/N] : " i
 case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 testCase
 ;;
 esac

testCase

If the input is invalid it will recall the function until it gets a valid input.

share|improve this answer

answered Sep 3 at 16:33

SivaPrasath

1

You can do by keeping switch case inside a function.

function testCase ()

 read -r -p "Would you like to continue [Y/N] : " i
 case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 testCase
 ;;
 esac

testCase

If the input is invalid it will recall the function until it gets a valid input.

share|improve this answer

answered Sep 3 at 16:33

SivaPrasath

1

share|improve this answer

share|improve this answer

answered Sep 3 at 16:33

SivaPrasath

1

answered Sep 3 at 16:33

SivaPrasath

1

answered Sep 3 at 16:33

SivaPrasath

1

1

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  Or until you run into a resource restriction or a maximum recursion depth limit.
  – Kusalananda
  Sep 3 at 16:35
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Thanks a lot it works!!
  – user308897
  Sep 3 at 16:42
  

  
  
  
  


• 
  
  
  

  
  8
  

  
  
  
  
  
  

  
  I wouldn't count on the shell being able to optimize the tail recursion, and given the usual procedural nature of shell scripts, I'd really suggest writing that loop out.
  – ilkkachu
  Sep 3 at 18:33
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  @Kusalananda If the user gives an incorrect answer to a simple yes/no question so many times you hit the recursion limit, he deserves to have the script crash.
  – Barmar
  Sep 3 at 21:45
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @Barmar A programmer should expect that the user will input anything, whether it's an incorrect answer enough times to hit a recursion limit, or eight gigabytes of null and control codes. Failing on a corner case like this is indicative of bad programming.
  – forest
  Sep 4 at 0:47
  
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  Or until you run into a resource restriction or a maximum recursion depth limit.
  – Kusalananda
  Sep 3 at 16:35
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Thanks a lot it works!!
  – user308897
  Sep 3 at 16:42
  

  
  
  
  


• 
  
  
  

  
  8
  

  
  
  
  
  
  

  
  I wouldn't count on the shell being able to optimize the tail recursion, and given the usual procedural nature of shell scripts, I'd really suggest writing that loop out.
  – ilkkachu
  Sep 3 at 18:33
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  @Kusalananda If the user gives an incorrect answer to a simple yes/no question so many times you hit the recursion limit, he deserves to have the script crash.
  – Barmar
  Sep 3 at 21:45
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @Barmar A programmer should expect that the user will input anything, whether it's an incorrect answer enough times to hit a recursion limit, or eight gigabytes of null and control codes. Failing on a corner case like this is indicative of bad programming.
  – forest
  Sep 4 at 0:47
  
  

  
  
  
  

3

3

Or until you run into a resource restriction or a maximum recursion depth limit.
– Kusalananda
Sep 3 at 16:35

Or until you run into a resource restriction or a maximum recursion depth limit.
– Kusalananda
Sep 3 at 16:35

Thanks a lot it works!!
– user308897
Sep 3 at 16:42

Thanks a lot it works!!
– user308897
Sep 3 at 16:42

8

8

I wouldn't count on the shell being able to optimize the tail recursion, and given the usual procedural nature of shell scripts, I'd really suggest writing that loop out.
– ilkkachu
Sep 3 at 18:33

I wouldn't count on the shell being able to optimize the tail recursion, and given the usual procedural nature of shell scripts, I'd really suggest writing that loop out.
– ilkkachu
Sep 3 at 18:33

1

1

@Kusalananda If the user gives an incorrect answer to a simple yes/no question so many times you hit the recursion limit, he deserves to have the script crash.
– Barmar
Sep 3 at 21:45

@Kusalananda If the user gives an incorrect answer to a simple yes/no question so many times you hit the recursion limit, he deserves to have the script crash.
– Barmar
Sep 3 at 21:45

@Barmar A programmer should expect that the user will input anything, whether it's an incorrect answer enough times to hit a recursion limit, or eight gigabytes of null and control codes. Failing on a corner case like this is indicative of bad programming.
– forest
Sep 4 at 0:47

@Barmar A programmer should expect that the user will input anything, whether it's an incorrect answer enough times to hit a recursion limit, or eight gigabytes of null and control codes. Failing on a corner case like this is indicative of bad programming.
– forest
Sep 4 at 0:47

add a comment | 

up vote
1
down vote

until [ "$i" = "0" ]
do
read -r -p "Would you like to continue [Y/N] : " i
case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 ;;
esac
done

share|improve this answer

answered Sep 3 at 18:21

GAD3R

22.7k154895

add a comment | 

up vote
1
down vote

until [ "$i" = "0" ]
do
read -r -p "Would you like to continue [Y/N] : " i
case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 ;;
esac
done

share|improve this answer

answered Sep 3 at 18:21

GAD3R

22.7k154895

add a comment | 

up vote
1
down vote

up vote
1
down vote

until [ "$i" = "0" ]
do
read -r -p "Would you like to continue [Y/N] : " i
case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 ;;
esac
done

share|improve this answer

answered Sep 3 at 18:21

GAD3R

22.7k154895

until [ "$i" = "0" ]
do
read -r -p "Would you like to continue [Y/N] : " i
case $i in
 [yY])
 echo -e "Resuming the script";;
 [nN])
 echo -e "Skipped and exit script"
 exit 1;;
 *)
 echo "Invalid Option"
 ;;
esac
done

share|improve this answer

answered Sep 3 at 18:21

GAD3R

22.7k154895

share|improve this answer

share|improve this answer

answered Sep 3 at 18:21

GAD3R

22.7k154895

answered Sep 3 at 18:21

GAD3R

22.7k154895

answered Sep 3 at 18:21

GAD3R

22.7k154895

22.7k154895

add a comment | 

add a comment |