QCad has been superseded by LibreCAD
On Ubuntu 9.10 - the QCad library location is /usr/share/qcad/libraries or /usr/share/librecad/library
Any dxf files put into that folder will appear as usable libraries within QCad. This is a powerful tool for sharing design, especially in Linux distributions dedicated to OSE's development.
Over time, we want to publish a Linux build dedicated to the work of OSE. See OSE Linux Build
apt-cache depends qcad
Depends: libc6 Depends: libfontconfig1 Depends: libgcc1 Depends: libice6 Depends: libjpeg62 Depends: libpng12-0 Depends: libqt3-mt Depends: libsm6 Depends: libstdc++6 Depends: libx11-6 Depends: libxext6 Depends: zlib1g Suggests: partlibrary Recommends: qcad-doc