If you installed a package manually from the command line, you can try:
Code:
sudo dpkg --remove calibre
or
Code:
sudo apt-get remove calibre
If you installed it otherwise, I suggest you find out exactly where it is installed by doing:
Code:
ls -l `which calibre`
That should tell you whether the "calibre" binary is a symbolic link to a binary someplace else (like "/opt/calibre/bin/calibre" or something). If it is, you probably have all of Calibre installed in a single directory. In that case, simply remove the directory and the symlinks to the binaries. If not, then you'll have to hunt down the individual Calibre files yourself and remove them, which I'm sorry to say is a pain. The "find" command is your friend to locate the files.