Using metacharacters in loops

Shell Programming and Scripting
1

Is there a way to use metacharacters in a loop or in an if[ ].
I want to allow a user to enter Y, y, Yes, yes, Yah, etc...
in a loop I tried:

read response
while [ "$response" = "[Yy]*" ]
do........

and

while [ "$response" = "\[Yy\]*" ]
do .........

this works for grep or egrep but not in loops
Why??????

2

"Why" is a tough question to answer.

But the Korn shell corrected this problem and several others by introducing the [[ syntax:

while [[ $response = [Yy]* ]]

will work. And there is no need to quote $response. Unlike the "[" command, "[[" works fine if $response is empty.

And a warning:

while [[ [Yy]* = $response ]]

will not work. The pattern must be on the right of the equals sign.

3

while [[ $response = [Yy]* ]]

doesn't work for me--but I'm using the Bourne shell.

4

The only Bourne shell built-in that uses patterns is the case statement. That's a possibility. But you may want to try a modern shell.

5

Thanks...Perderabo
You're an amazing resource!!!