Unix while loop shell script

Question

Hi I am trying to execute the below code in unix but the script is going in infinite loop. Though the code looks to be perfect, i am unable to debug the error:

answer=y
while [ "$answer" = "y" ]
do
echo " Enter the word and filename"
read pname flname
grep "$pname" "$flname" > newlist
echo " Enter any more string to be searched (y/n)? "
read anymore
case anymore in
y) answer=y ;;
n) answer=n ;;
esac
done

You lack the dollar sign on the variable. case $anymore pro case anymore which just examines the static string "anymore". Voting to close as simple typo. — tripleee
– tripleee, Commented Jun 2, 2016 at 8:10
also read without -r will mangle backslashes. Shouldn't be an issue here anyway. — sjsam
– sjsam, Commented Jun 2, 2016 at 8:26

SLePort · Accepted Answer · 2016-06-02 09:22:09Z

3

The expression after case should be the value of the variable read at previous line :

case "$anymore" in

instead of :

case anymore in

Update :

As @Jens mentionned, you can omit to double-quote the variable here as word splitting is not performed on expansions inside case (from http://mywiki.wooledge.org/WordSplitting#line-106).

edited Jun 2, 2016 at 9:22

answered Jun 2, 2016 at 8:12

SLePort

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7 Comments

user3134805 Over a year ago

Thanks a lot Kenavoz... Its too bad from my side..i m in the learning phase of unix shell scripting...

Julien Lopez Over a year ago

I think you meant to say that the expression after case is not a variable. In your solution, it's a variable expansion so a value. And you may want to put $anymore in quotes to avoid errors.

user3134805 Over a year ago

Thanks Julien..as sugested by Kenavoz and you, the code is working fine with $anymore..

Jens Over a year ago

@JulienLopez There is no word-splitting performed on the expansion of a case expression. It is one of the few safe places to not bother with double quotes around a single parameter substitution. The other place is in variable assignments, foo=$bar.

SLePort Over a year ago

@Jens Thanks for your comment. I did not remove the quotes here as In either case, quoting anyway will not break anything. So if in doubt, quote!.

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