Update information without creating new line in batch - windows

Question

The script I had been working on reads all folders on the CD-ROM drive "i" and searches for mp3 files, copying them onto the destination "e:\MP3\new".
#ECHO off
setlocal enabledelayedexpansion
cd /d "i:\"
set count=1
for /r %%d in (*.mp3) do (
set /a count+=1
)
echo There were %count% files found
set countb=1
for /r %%g in (*.mp3) do (
set /a countb+=1
echo|set /p = File: !countb!/%count%
copy "%%g" "e:\MP3\new" > nul
)
endlocal
Let´s suppose in this example that 115 files were found.
What I get from the above code:
There were 115 files found
File: 1/115 File: 2/115 File: 3/115 File: 4/115 File: 5/115 (...) File: 115/115
What I want:
There were 115 files found
File: X/115 where X will be constantly updated on the screen each time an mp3 file is successfully copied
Any help to fix that?

Answer 1

Firstly, you are initialising your counters wrongly, they should be set to zero (like set count=0) rather than one to get the correct numbers.
Secondly, you should replace echo|set /p = by < nul set /P =, because the pipe (|) is slower than simple (input) redirection (<) since it creates new cmd instances for either side.
To move the cursor in the Command Prompt window back to the beginning of the current line, you need to write the carriage-return character first. However, you cannot use this character as the first one with set /P, because it is going to be removed, together with other leading white-space characters. So you need another invisible character preceding the carriage-return that is not going to be removed; let us choose the back-space character.
Therefore, the fixed code may look like this, for instance:
#echo off
setlocal EnableDelayedExpansion
rem // Gather the back-space character:
for /F %%B in ('prompt $H ^& for %%Z in ^(.^) do rem') do set "BS=%%B"
rem // Gather the carriage-return character:
for /F %%C in ('copy /Z "%~f0" nul') do set "CR=%%C"
cd /D "I:\"
set /A "count=0"
for /R %%d in ("*.mp3") do (
set /A "count+=1"
)
echo There were %count% files found.
set /A "index=0"
for /R %%g in ("*.mp3") do (
set /A "index+=1"
< nul set /P ="%BS%!CR!File: !index!/%count%"
copy "%%~g" "E:\MP3\new\" > nul
)
endlocal