IFS giving Incorrect output

Question

I have a port number file map.ini:

50051=1
50052=1
50053=1
50054=1
50055=1
50056=1

and a script sample.sh whose contents are:

#!/bin/bash
file=map.ini

while IFS='=' read -r port varPortStatus
do
        if [[ $varPortStatus -eq "1" ]]; then
                printf "Available port is %s" $port
                printf "Status is %d." $varPortStatus.
                return 0
        fi
done < "$file"
echo "No port is available"

Expected output I need is:

Available port is 50051
Status is 1

I can do this using sed or cut command manipulation. But I need to understand with IFS here. I am getting output as:

")syntax error: invalid arithmetic operator (error token is "
")syntax error: invalid arithmetic operator (error token is "
")syntax error: invalid arithmetic operator (error token is "
")syntax error: invalid arithmetic operator (error token is "
")syntax error: invalid arithmetic operator (error token is "
")syntax error: invalid arithmetic operator (error token is "
No port is available

Please tell where am I doing wrong?

Answer 1

from the output seems there's may be a dos line ending \r in map.ini or in sample.sh, try dos2unix map.ini, or cat -ve map.ini to verify.

if the input file can't be modified \r character can be removed in bash

while IFS='=' read -r port varPortStatus
do
    varPortStatus=${varPortStatus%$'\r'}
    if [[ $varPortStatus -eq "1" ]]; then
            printf "Available port is %s\n" $port
            printf "Status is %d.\n" $varPortStatus
    fi
done < "$file"

Note also fixes \n added to format, . removed after $varPortStatus and return valid only in a function or a sourced script.