Off topic:Converting the following batch script to linux shell

Question

[User 6777]

I am currently migrating to ubuntu from my windows system. Now I am learing to convert all my batch scripts into linux shell. Although the common commands are more or less similar, but I found it difficult for the following set of commands in windows cmd:

setlocal
:PROMPT
SET /P AREYOUSURE=USE Consensus Disorder Regions (Y) / User Selection (N):
IF /I "%AREYOUSURE%" NEQ "Y" GOTO FINISH1

echo              Options:
echo.
echo              1)    IUPRED(Long) + PONDR(VSL2b) + DisEMBL(REM465)
echo.
echo              2)    IUPRED(Long) + PONDR(VSL2b) + DisEMBL(COILS)
echo.
echo              3)    IUPRED(Long) + PONDR(VSL2b) + DisEMBL(HOTLOOPS)
echo.
echo              4)    IUPRED(Short) + PONDR(VSL2b) + DisEMBL(REM465)
echo.
echo              5)    IUPRED(Short) + PONDR(VSL2b) + DisEMBL(COILS)

CHOICE /C 12345 /M "Enter your choice:"

:: Note - list ERRORLEVELS in decreasing order

IF ERRORLEVEL 5 GOTO choice5
IF ERRORLEVEL 4 GOTO choice4
IF ERRORLEVEL 3 GOTO choice3
IF ERRORLEVEL 2 GOTO choice2
IF ERRORLEVEL 1 GOTO choice1

:choice1
perl script.pl input1.txt >> Output1.txt
GOTO End
:choice2
perl script.pl input2.txt >> Output2.txt
GOTO End
:choice3
perl script.pl input3.txt >> Output3.txt
GOTO End
:choice4
perl script.pl input4.txt >> Output4.txt
GOTO End
:choice5
perl script.pl input5.txt >> Output5.txt

:End


:FINISH1
endlocal
....
Next scripts..
...

These commands first prints few options, takes user choice and execute one perl script according to user choice. I notice a function called "setlocale" in linux, but I don't understand how to use that in the above problem.

I appreciate all advice and suggestion.

Thanks