ERROR 4: Failed to open file /dev/stdout.xsd for schema output

[peifer]

OGR's GML driver tries (and fails) to create a schema file at /dev/stdout.xsd. The command I used was: ogr2ogr -f gml /dev/stdout test.shp

As Even R wrote today on the gdal-dev mailing list: But yes, it lacks the special case to recognize /dev/stdout as a particular value where you must not try to write a file, which would avoid the error.

[Even Rouault]

r23022 /trunk/ (21 files in 11 dirs): 
OGR drivers: mentions in the doc that BNA, CSV, GPX, KML, GeoRSS, GML, LIBKML,
GeoJSON, PGDump and shapefile (non exhaustive list...) support the VSI File API;
for the ones supporting outputing to standard output (all of the above except
shapefile), accept both /dev/stdout and /vsistdout/ as filenames; remove
'stdout' as a valid alias that could be used in some of them (#4225, #4226)