Loop through files in folder, replace content and Save as new Name - batch-file

Question

I need to loop through filed end with .edi in my folder, replace a character in the content and then save the file in another folder with "_updated"on the end.
e.g.
C:/Test/FileName.edi replace ' in file with ^ and save the file into C:/Test/Output/FileName_Updated.edi
I've tried the following code and it works up until the saving the filename part, I've got confused somewhere, I don't usually write batch scripts:
#echo off
setlocal enabledelayedexpansion
for %%f in (C:\Test\*.edi) do (
set "input=C:\Test\"
SET "output=C:\Test\Output\"
for %%a in (%%f) do (
set "output=%output%%%~na_update.%%~xa"
)
(for /f "delims=" %%i in (%%f) do (
set "line=%%i"
setlocal enabledelayedexpansion
set "line=!line:'=^!"
echo(!line!
endlocal
)))>> %output%
)

Answer 1

Figured it out with help from aschipfl
#echo off
setlocal enabledelayedexpansion
for %%f in (C:\Users\CHRW\Desktop\EDILocalTest\*.edi) do (
SET "output=C:\Users\CHRW\Desktop\EDILocalTest\Output\"
for %%a in (%%f) do (
set "outputfile=!output!%%~na_update%%~xa"
)
(for /f "delims=" %%i in (%%f) do (
set "line=%%i"
setlocal enabledelayedexpansion
set "line=!line:'=^!"
echo(!line!
endlocal
))>> !outputfile!
)

Answer 2

#echo off
setlocal enabledelayedexpansion
for %%f in (C:\Test\*.edi) do (
set "input=C:\Test\"
SET "output=C:\Test\Output\"
(for /f "delims=" %%i in (%%f) do (
set "line=%%i"
rem setlocal enabledelayedexpansion
set "line=!line:'=^!"
echo(!line!
rem endlocal
)))>> "%output%%%~nf_update.%%~xf"
)
Since you were changing the value of output within the loop, the redirection should have been to !output! not %output% - the changed value of output, not the value of output at the time the outer for loop was parsed.
Since %%f contains a filename, there's no need to re-parse it. Easier to construct the output filename in-line
Since delayedexpansion has been invoked at the start of the procedure, there's no need to re-invoke it and close the new invocation. I've REMmed-out those lines as it may be that you are presenting abbreviated code.