Loop for the user input in bash-CodePudding

I am trying to build loop for the user input until I get a specific input for example I want to stop the loop when the input = 4 and print siiiiii but the problem is the program stuck in the loop how can I set a new value for the loop input ?

#!/bin/bash

value=4

echo Enter the number:
read $input
while [ $input !=  $value ]
do
    echo "The input must be between 1 and 4"
    read input2
    input = $input2
done

echo siiiiiiiiiiiiiiiiiii

CodePudding user response：

#!/bin/bash

value=4

echo Enter the number:
while read input; do
    if [ "$input" = "$value" ]; then break; fi
    echo "The input must be between 1 and 4" >&2
done

echo siiiiiiiiiiiiiiiiiii

You could also write:

while read input && [ "$input" != "$value" ]; do
    echo "The input must be between 1 and 4" >&2
done

You might prefer to use -eq and -ne since you are doing integer comparisons, as this gives you additional error messages. Whether or not those error messages are useful is a design decision:

while read input && ! [ "$input" -eq "$value" ]; do
    echo "The input must be between 1 and 4" >&2
done

The 4 main issues with your original code are: failure to quote variables, incorrect attempt at the assignment input = $input2 (you cannot have space around the =), incorrect use of $ in the read $input command, and failure to use the standard while read varname idiom. There are probably some other minor issues as well, but those jump out.