Shell Programming and Scripting

read -p "How many tags to enter:" cars
        echo $cars | grep "[a-zA-Z]"
        if [ $? -eq 1 ]
        then
        read -p "Please enter car year:" yearmodel
        else
        read -p"Invalid number. Please re-enter:" $cars
        exit

  read -p "Please enter car year:" yearmodel

uname -a
echo $SHELL

      
read -p "How many cars to enter:" cars
until "$cars" [ -ne 1 ] && grep "[a-zA-Z]"
do
read -p "Invalid number. re-enter:" cars
done

while true
do
   read -p "How many cars to enter: " tot
   [ $tot -ge 0 ] 2>/dev/null && break
   echo "Invalid number. re-enter"
done
num=0
while [ $num -lt $tot ]
do
    read -p "Enter car #$((++num)): " cars[num]
done
num=0
while [ $num -lt $tot ]
do
   echo "Car #$((++num)) is ${cars[num]}"
done

while true
do
   read -p "How many cars to enter: " tot
   [ $tot -ge 0 ] 2>/dev/null && break
   echo "Invalid number. re-enter"
done
for((num=1; num<=tot; num++)) {
    read -p "Enter car #$num: " cars[num]
}
for((num=1; num<=tot; num++)) {
   echo "Car #$num is ${cars[num]}"
}

while true
do
   read -p "How many cars to enter: " tot
   [ $tot -ge 0 ] 2>/dev/null && break
   echo "Invalid number. re-enter"
done

$ cat gangsta
#!/bin/bash
while true
do
   read -p "How many cars to enter: " tot
   [ $tot -ge 0 ] 2>/dev/null && break
   echo "Invalid number. re-enter"
done
$ ./gangsta
How many cars to enter: two
Invalid number. re-enter
How many cars to enter: -1
Invalid number. re-enter
How many cars to enter: 3
$./gangsta
How many cars to enter: 5
$