How to use user input into a while loop

Question

Well, Im trying to practice a bit of shell script but Im stuck at this while loop excercise. I simply want to use whatever number the use inputs as the loop`s condition.

#!/bin/bash

a=0
input=""
echo "Type any number"

read $input

while [$a -lt $input]
do
   echo $a
   a=`expr $a + 1`
done

For a start, most of your script is inside a string. Once you've taken care of that, use shellcheck.net — Tom Fenech
– Tom Fenech, Commented Sep 19, 2016 at 15:59

pawel.panasewicz · Accepted Answer · 2016-09-21 18:44:17Z

2

You might wonder to have such script:

#!/bin/bash

a=0
input=""
echo "Type any number" #here you forgot to close string with "

read input  #here you don't need $


while [ $a -lt $input ]  #note extra spaces after [ and before ]
                         #tricky part here is that '[' is a program 
                         #and '$a -lt $input ]' are just its params
                         #this is why you need add extra spaces     
do
   echo $a
   a=`expr $a + 1`

done

edited Sep 21, 2016 at 18:44

answered Sep 19, 2016 at 16:04

pawel.panasewicz

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