shell

# Hello World Program in Bash Shell
foo=2
echo "Hello World!"
echo $foo
if [ "$foo" -ge 3 ]; then
    echo "Greater than"
else
    echo "Less than"
fi

first='Madhu'
lastname='Naidu'
middle='Naidu'
surname='Yanamala'
if [  $first=='Madhu' -a $lastname=='Naidu' ]; then
    echo "First" $first
    echo "Last" $lastname
else
    echo $middle
fi

if [ $first=='Naidu' -o $lastname=='Yanamala' ]; then
    echo "Second" $first
    echo $lastname
else
    echo "Else" $lastname
fi
if [ 'mad'='mad' ]; then
    echo 'mad'
else
    echo 'else mad'
fi
name=
if [ -z  "$name" ]; then
    echo "True empty"
fi
if [ "$first"='Madhu' ] && [ "$surname"=~"n" ]; then
    echo "Surname" $surname
    echo "First" $first
fi

if [[ "$middle" == "Naidu" && "$first"="Madhu" ]]; then
    echo "And" $middle
else
    echo "And false"
fi
if [ "$first"=="Madhu" ]; then
    echo "True" $first
    if [ "$surname"=="Yanamala" ]; then
        echo "True" $surname
    fi
fi
if [ "$first"="Madhu" ] && [ "$surname"="Yanamala" ]; then
    echo "TRUE" $first $surname
fi