bashシェルwhileループが条件式を超える

j私の質問はvalueとivaluereachのようです。6誰iでも5説明できますか？

i=0;
j=0;
echo "values of $i and $j" > debug.txt;
while [ $j -le 5 ]
do
    j=expr $j + 1
    i=expr $i + 1
    echo "values of $i and $j" >> debug.txt
done;
cat debug.txt;

出力：

value of i is  0 and j is  0
value of i is  1 and j is  1
value of i is  2 and j is  2
value of i is  3 and j is  3
value of i is  4 and j is  4
value of i is  5 and j is  5
value of i is  6 and j is  6