Set /p %foo% doesn't function as expected - batch-file

Question

I have a problem with my code. I am trying to make a "hacker tool" with the tree command. Here is my code:
#echo off
title $userOne ProxyMatrix
color a
echo Hello $userOne,
echo Please enter search function for today's commands:
set /p %commands%=""
:redo
echo Specify Storage Device
set /p %drive%=""
title $userOne ProxyMatrix: Running on %drive% drive at %random% bits per nano
color C
tree %drive% /f
:runagain
color a
echo Run again?
set /p %redo%=""
if %redo%="yes" goto redo
else if %redo%="y" goto redo
else if %redo%="Y" goto redo
else if %redo%="Yes" goto redo
else if %redo%="no" goto end
else if %redo%="No" goto end
else if %redo%="n" goto end
else if %redo%="N" goto end
else echo Thats not a valid answer!
pause
goto runagain
:end
echo Thank you for choosing InGen, inc.
pause
I realize that this won't "hack" anything, its more of a novelty. The problem is, the set /p %redo% and the if/else if statements don't work. They just quit the program. Can someone explain what i'm doing wrong? Thanks.

Answer 1

Syntax is set /p variable=prompt.
Instead of set /p %redo%="" write set /p redo="" or even better set /p "redo="
EDIT
your if syntax is broken too.
Syntax is: if value1==value2 command or if value1==value2 (command1) else (command2)
"Best Practice is to enclose both sides of the comparison with quotes (to avoid syntax errors with empty values or contained spaces):
if "%variable"=="value" echo yes
I would shorten the code to:
set /p %redo%=""
if /i "%redo:~0,1%"=="y" goto redo
if /i "%redo:~0,1%"=="n" goto end
else echo Thats not a valid answer!
/i tells if to ignore capitalization
%variable:~0,1% means "take a substring starting with the first letter (counting starts at 0) with length=1 (so it takes the first letter)
(there is no else needed)