CODEWITHSUNDEEP
shell
user11580777
user11580777

Reputation:

How to pass a value to read input before being prompted?

I have shell script prompting an answer y/n. at the prompt before giving input, I used control-c signal which calls Signal Handling function. In Signal Handling function there is a prompt "q" to exit or "y" and "y" should be used with the FIRST read prompt.

I tried to (( echo "y" | read )) but didn't work

      ==========================================
           This is part of my script:

IntHandle ()

{ 
   echo -e "\nUse 'q' to quit "
   read var1 
   if [[ $var1 == q ]]
   then
        exit 1
   else
        echo "y" | read ----->here I need "y" to be an input to read prompt 
                             directly and being saved in "ans" variable in 
                             main body where I used control-c 
   fi
 }


trap 'IntHandle' SIGINT
read -p "no valid user id entered, new user ids? [y\n]: " ans ----> here 
                                  used control-c signal before give y/n to ans
if [[ $ans == "y" ]]
then 
     read -p " username :" name
fi
      .
      .
      .
      .
      .

================

output should be like below:

no valid user id entered, new user ids? [y\n]: #control-c entered

' Use 'q' to quit ' y ------> here "y" entered rather "q" in Siganl Handeling function then it is saved in "ans" variable which gets the condition true to prompt a username.

usernames: Larry -----> the name which is entered after true condition. . . .

Upvotes: 0

Views: 274

Answers (1)

Dennis Williamson
Dennis Williamson

Reputation: 360605

Instead of

echo "y" | read

Try:

ans=y

The definition of the trap function needs to be made before the trap is triggered. So I would move it to the top of the file.

When the function finishes, control is returned to the read statement that was interrupted by the Ctrl-C. So what I would do instead of echo "y" | read or ans=y is to reissue the original prompt:

IntHandle ()
{ 
  echo -e "\nUse 'q' to quit "
  read var1 
  if [[ $var1 == q ]]
  then
       exit 1
  else
       echo -n 'no valid user id entered, new user ids? [y\n]: '
  fi
}

Upvotes: 1

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