Can I use "GZSDF" to convert an URDF file into a SDF file???

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Can I use "GZSDF" to convert an URDF file into a SDF file???

-I have my urdf(01-myfirstyo.urdf) in the next path:

/home/john/ros/01-myfirstyo.urdf

• I tried several methods to convert an urdf file into a sdf file (with gzdf in ROS FUERTE) and they didnt work:

FIRST TRY:

john@john-K53SD:/opt/ros/fuerte/stacks/simulator_gazebo/gazebo$ source setup.bash

john@john-K53SD:/opt/ros/fuerte/stacks/simulator_gazebo/gazebo$ ./gazebo/bin/gzsdf print /home/john/ros/01-myfirstyo.urdf

Warning [parser.cc:348] Gazebo SDF has no gazebo element

Error [parser.cc:263] parse as old deprecated model file failed.

Error: SDF parsing the xml failed

SECOND TRY:

john@john-K53SD:/opt/ros/fuerte/stacks/simulator_gazebo/gazebo$ source setup.bash

john@john-K53SD:/opt/ros/fuerte/stacks/simulator_gazebo/gazebo$ ./gazebo/bin/gzsdf convert /home/john/ros/01-myfirstyo.urdf

Error: Unknown option[convert] This tool provides information about SDF files.

gzsdf <command> [file]

Commands:

describe   Print the SDF format.

check      Check the SDF format for the given file.

print      Prints SDF, useful for debugging parser and as a conversion tool.

Please tell me what am i doing wrong???