[SOLVED] Loop with user input

Masiel · 02-12-2021, 01:32 PM

Hi! I am very new to this and I am reaching a roadblock that I have no idea how to get around. I am trying to create a script that will prompt the user to enter First Name, Last Name, City until exit is entered in the First Name. Displayed like this

First Name: Jane
Last Name: Doe
City: Dayton

First Name: John
Last Name: Smith
City: Cincinnati

First Name: exit

Jane Doe Dayton
John Smith Cincinnati

So far I have this:

until [[ $Fname = "exit" ]];
do

read -p 'First Name: ' Fname
read -p 'Last Name: ' Lname
read -p 'City: ' Cname

echo $Fname $Lname $Cname

However, its not stopping after First Name: exit, it continues to Last Name, City, then it echo, but only the second pass of the loop. How do I get it to echo both passes? And how do I get it to stop after exit is entered?

This is part an of assignment for class, and we are like 3 weeks in, so I am very new. If that info is needed. Thanks so much for your help!

computersavvy · 02-12-2021, 01:48 PM

The Fname is the first entry and does not get tested until the loop completes. Put a test of the Fname value with an exit statement right after the Fname is entered. This way it will exit the loop immediately rather than continuing the loop to the end

Also, for every "do" it needs to end with a "done"

One quick reference for use now and later!
https://tldp.org/guides.html

teckk · 02-12-2021, 02:10 PM

Code:

while :; do
    read -p "Enter first name :" fname
    if [ "$fname" = "exit" ]; then
        exit
    fi
    read -p "Enter last name :" lname
    read -p "Enter city name :" cname
    echo ""$fname" "$lname" "$cname""
done

Masiel · 02-12-2021, 03:53 PM

Thanks!

However, that code will echo right after each first name: last name: city: block, instead of at the end and reflecting both sets. With exit set there, it exits automatically when "exit" is entered for first name: and doesn't echo.

Masiel · 02-12-2021, 03:57 PM

Oh, I also just noticed I made a mistake with the final output. I edited original post to reflect it. It is supposed to look like this:

First Name: Jane
Last Name: Doe
City: Dayton

First Name: John
Last Name: Smith
City: Cincinnati

First Name: exit

Jane Doe Dayton
John Smith Cincinnati

shruggy · 02-12-2021, 04:40 PM

Replace exit with break and read each set of data into an array element. Then, after break from the while loop, loop over all the array elements and print them.

Code:

#!/bin/bash
declare -a data
while :
do
  read -p 'First name: ' fname
  [[ $fname == 'exit' ]] && break
  read -p 'Last name: ' lname
  read -p 'City: ' cname
  data+=("$fname $lname $cname")
  echo
done
echo
for i in "${data[@]}"
do
  echo "$i"
done

Masiel · 02-12-2021, 04:58 PM

Thanks! And thanks for the explanation. That worked!

MadeInGermany · 02-12-2021, 04:59 PM

Yes, break is correct.
It ends the loop; the script continues after the loop.

An alternative:

Code:

until
  read -p 'First Name: ' Fname
  [[ $Fname == "exit" ]]
do
  read -p 'Last Name: ' Lname
  read -p 'City: ' Cname

  echo $Fname $Lname $Cname
done

The last statement before the do gives the exit status that matters.

computersavvy · 02-12-2021, 05:39 PM

Quote:

Originally Posted by Masiel

Oh, I also just noticed I made a mistake with the final output. I edited original post to reflect it. It is supposed to look like this:

First Name: Jane
Last Name: Doe
City: Dayton

First Name: John
Last Name: Smith
City: Cincinnati

First Name: exit

Jane Doe Dayton
John Smith Cincinnati

You then need to build an array of responses and echo the array at the end. Read the first document in the link I sent earlier on how to do that. I doubt what you echo at the end should contain the exit command.

This might do what you want

Code:

#!/bin/bash

((count=1))

while :; do
    read -p "Enter first name :" fname
    if [ "$fname" = "exit" ]; then
        break
    fi
    data1[$count]=$fname
    read -p "Enter last name :" lname
    data2[$count]=$lname
    read -p "Enter city name :" cname
    data3[$count]=$cname
    (( count++ ))
done


if [ $count -gt 1 ]; then
    num=1
    while [ $num -lt $count ]; do
       echo "${data1[$num]}  ${data2[$num]}    ${data3[$num]}"
       (( num++ ))
   done
else
   echo "No data entered"
fi

Again, read up on what each of those constructions do to really learn. Copying does nothing to assist in learning.

shruggy · 02-12-2021, 06:00 PM

A POSIX shell solution (incorporating MadeInGermany's suggestion)

Code:

#!/bin/sh
set --
until
  read -p 'First name: ' fname
  [ 'exit' = "$fname" ]
do
  read -p 'Last name: ' lname
  read -p 'City: ' cname
  set -- "$@" "$fname" "$lname" "$cname"
  echo
done
echo
while [ $# -gt 0 ]
do
  echo "$1" "$2" "$3"
  shift 3
done

Masiel · 02-12-2021, 06:10 PM

Computersavvy, thanks for your responses, and your link. It’s going to be a great resource. I love the different codes people have suggested so I can compare and learn how it works. Everyone’s codes and suggestions have been so helpful. Thanks everyone.

computersavvy · 02-12-2021, 06:20 PM

You notice there are many ways to do the same thing. Use what works for you and enjoy.