Finding the max and min values and printing the line from a file

Question

I have a file which has numbers at the first column.

100,red
101,blue
102,black

I should write a shell script that it will print the line with the max and min numbers.

max=0
cat file.txt|while read LINE
do
    fir=`echo $LINE|awk '{print $2}'`
    sec=`echo $LINE|awk '{print $3}'`
    if [ $fir -gt $max ]; then
       max=$fir
    fi
    if [ $sec -gt $max ];then
        max=$sec
    fi
done

grep $max file.txt

This is what i tried so far for finding the max.

Answer 1

For min value:

[bash]$ cut -f1 -d"," file_name | sort -n | head -1

For max value:

[bash]$ cut -f1 -d"," file_name | sort -n | tail -1