character manipulation in file cmd - text

Question

this is file.txt
hello
hai
So i wanna create a program that will read this file. and then replace every ALPHABET with the succeeding one. keeping all numbers and other symbols intact.
so the file.txt would become
ifmmp
ibj
current have tried reading every \n and then reading every character in the line, but echoing them would result in it being in different lines
ie
for /f "delims=" %%i in ('^<%path% findstr /n "^"') do (
set "line=%%i"
setlocal enabledelayedexpansion
set "line=!line:*:=!"
set "num=-1"
:loop
set /a num=num+1
call set "name2=%%line:~%num%,1%%"
if defined name2 (
rem set /a name2+=1 this statement wont work
echo %name2%
goto :loop )
)
but then the output i get is
echo is off
e
l
l
o
any ideas?

Answer 1

The set /a command does only work with numbers, you can try this:
#echo off&setlocal
set "alfa=abcdefghijklmnopqrstuvwxyza"
set "test=hello hai"
set /a num=0
:loop
call set "char=%%test:~%num%,1%%"
if not defined char goto:eof
call set "alf1=%%alfa:*%char%=%%"
if "%char%" neq " " echo %alf1:~0,1%
set /a num+=1
goto:loop
..output is:
i
f
m
m
p
i
b
j

Answer 2

Here is a ROT13 batch file - what you are describing is a ROT1 translation. Maybe this will work for you as it is, or give you ideas and you can modify it.
#echo off
:: by aacini
:: program works as a filter, that is, it read lines from keyboard (stdin) and send output to screen (stdout). "type filetext.txt|rot13.bat" or "rot13.bat < filetext.txt"
:: with d benham update
#echo off
:: simple rot-13 conversion filter program
setlocal disableDelayedExpansion
set lower=abcdefghijklmnopqrstuvwxyz
set upper=ABCDEFGHIJKLMNOPQRSTUVWXYZ
for /l %%a in (0,1,25) do (
set /a "rot13=(%%a+13)%%26"
setlocal enableDelayedExpansion
for %%b in (!rot13!) do for /f "tokens=1-4" %%A in (
"!lower:~%%a,1! !lower:~%%b,1! !upper:~%%a,1! !upper:~%%b,1!"
) do (
endlocal
set "lower%%A=%%B"
set "upper%%C=%%D"
)
)
for /f "delims=" %%a in ('findstr /n "^"') do (
set "line=%%a"
setlocal enableDelayedExpansion
set "line=!line:*:=!"
set output=
if defined line (
set /a len=0
for /l %%b in (12,-1,0) do (
set /a "len|=1<<%%b"
for %%c in (!len!) do if "!line:~%%c,1!" equ "" set /a "len&=~1<<%%b"
)
for /l %%b in (0,1,!len!) do (
set "char=!line:~%%b,1!"
if defined lower!char! for /f delims^=^ eol^= %%c in ("!char!") do (
if "!lower:%%c=%%c!" neq "!lower!" (
set "char=!upper%%c!"
) else set "char=!lower%%c!"
)
set "output=!output!!char!"
)
)
echo(!output!
endlocal
)