Two possibilities:

• Use wildcards to process all files in a directory:

FOR %%F in (D:\Karten\shp\Gemeinden\*.shp) DO ogr2ogr -t_srs EPSG:31466 D:\Karten\shp\neu\%%~nxF %%F

• Use quotation marks around path and filename:

ogr2ogr -t_srs EPSG:31466 "D:\Karten\shp\Test 1.shp" "D:\Karten\shp\Test 2.shp"

Two possibilities:

• Use wildcards to process all files in a directory:

FOR %%F in (D:\Karten\shp\Gemeinden\*.shp) DO ogr2ogr -t_srs EPSG:31466 D:\Karten\shp\neu\%%~nxF %%F

• Use quotation marks around path and filename:

ogr2ogr -t_srs EPSG:31466 "D:\Karten\shp\Test 1.shp" "D:\Karten\shp\Test 2.shp"

EDIT

This one works for me:

for /R %%F in (*.shp) do ogr2ogr -f "KML" "%%~dpnF.kml" "%%F"

Two possibilities:

1. Use wildcards to process all files in a directory:

FOR %%F in (D:\Karten\shp\Gemeinden\*.shp) DO ogr2ogr -t_srs EPSG:31466 D:\Karten\shp\neu\%%~nxF %%F

2. Use quotation marks around path and filename:

ogr2ogr -t_srs EPSG:31466 "D:\Karten\shp\Test 1.shp" "D:\Karten\shp\Test 2.shp"

Two possibilities:

• Use wildcards to process all files in a directory:

FOR %%F in (D:\Karten\shp\Gemeinden\*.shp) DO ogr2ogr -t_srs EPSG:31466 D:\Karten\shp\neu\%%~nxF %%F

• Use quotation marks around path and filename:

ogr2ogr -t_srs EPSG:31466 "D:\Karten\shp\Test 1.shp" "D:\Karten\shp\Test 2.shp"