Find and Replace one string with another inside the file using DOS batch

Wow, this thread just keeps getting revived from the grave. Fun.

There is a way to do this in batch, though there are much better tools out there to accomplish the task as shown throughout the thread. The batch method is outlined and not fully coded below:

This command would be used for one file and would need to be embedded in another for command if multiple files were needing to be changed.
for /f "delims=" %%G in (changefile.txt) do (
  set oldstring=%%G
  set newstring=!oldstring:~0,  52=0,  21!
  echo !newstring!>>temp.txt
)
del changefile.txt
ren temp.txt changefile.txt

Again, this could be run on multiple files using this for command embedded into another for command that would determine what is placed in the "changefile.txt" area. Obviously you could put multiple "set newstring=" commands in if there were multiple changes that were needing to be made.

Can we let this thread die now? It has lived a long life and should be allowed to rest in peace.
 

for /f "delims=" %%G in (changefile.txt) do (
  set oldstring=%%G
  set newstring=!oldstring:~0,  52=0,  21!
  echo !newstring!>>temp.txt
)
del changefile.txt
ren temp.txt changefile.txt

One error: there is no ~ after the colon in the set newstring line. It should read:
set newstring=!oldstring:0,  52=0,  21!