david@myhost:~$ sudo pacman -S pacman
resolving dependencies...
looking for inter-conflicts...

Targets (18): linux-api-headers-3.1.6-1  glibc-2.15-5  xz-5.0.3-1
              libarchive-3.0.3-3  run-parts-4.2.1-1  ca-certificates-20111211-1
              libssh2-1.4.0-1  curl-7.24.0-2  pth-2.0.7-4  libusb-compat-0.1.3-2
              gnupg-1.4.12-1  libksba-1.2.0-2  libassuan-2.0.3-1  pinentry-0.8.1-3
              dirmngr-1.1.0-3  gnupg2-2.0.18-1  gpgme-1.3.1-2  pacman-4.0.2-1

Total Download Size:    0.00 MB
Total Installed Size:   66.15 MB

Proceed with installation? [Y/n] Y
checking package integrity...
(18/18) checking for file conflicts                [##########################] 100%
error: failed to commit transaction (conflicting files)
libusb-compat: /usr/bin/libusb-config exists in filesystem
libusb-compat: /usr/include/usb.h exists in filesystem
libusb-compat: /usr/lib/libusb-0.1.so.4 exists in filesystem
libusb-compat: /usr/lib/libusb-0.1.so.4.4.4 exists in filesystem
libusb-compat: /usr/lib/libusb.a exists in filesystem
libusb-compat: /usr/lib/libusb.so exists in filesystem
libusb-compat: /usr/lib/pkgconfig/libusb.pc exists in filesystem
Errors occurred, no packages were upgraded.
david@myhost:~$