CODEWITHSUNDEEP
linuxbashshell
Rizal Fakhri
Rizal Fakhri

Reputation: 57

How to ask user to input and that's should be required

From a shell script, I want to ask the user to input data such as database name, database user etc.

When the user inadvertently presses the enter key, the input is blank. How do I make the input required? If the input is blank, the script asks that question again?

My current script, but maybe it doesn't work as I expected.

#!/bin/bash
# Clear terminal first
clear

echo -n "Your Database Name : "
read dbname
if [ "$dbname" = "" ]; then
   echo "ANSWER CANNOT BE BLANK!"
   echo -n "Your Database Name : "
   read dbname
else
... another code here

But this does not rule out the possibility that the user does not accidentally (or even perhaps on purpose) hit the enter key – how many if else condition do I have to make?

Upvotes: 1

Views: 1194

Answers (2)

Ruslan Osmanov
Ruslan Osmanov

Reputation: 21502

Use a loop: 

#!/bin/bash -

clear

echo -n "Your Database Name: "

while read dbname; do
  test "$dbname" != "" && break
  echo "ANSWER CANNOT BE BLANK!"
  echo -n "Your Database Name : "
done

echo "dbname = $dbname"

Edit: fix for Ctrl-D

The above-mentioned code leaves an empty string, if the user enters Ctrl-D. The following version handles this case:

#!/bin/bash -

clear

until read -r -p "Your Database Name: " db && test "$db" != ""; do
  continue
done

echo "db='$db'"

Note, we use the Bash builtin read command. If the user enters Ctrl-D(manual end-of-file), the read command exits with non-zero status, which is interpreted as error. See info bash 'read'.

This version will also work in non-interactive mode:

echo -e "\n name \n" | ./script.sh

Upvotes: 0

SLePort
SLePort

Reputation: 15471

You may use an infinite loop and break if input is not empty:

while true; do
  echo -n "Your Database Name: "
  read dbname
  if [[ "$dbname"  != "" ]]
  then
    echo "dbname = $dbname"
    break
  fi
done

Upvotes: 4

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