Thanks Torsten! I installed cmtk with sudo apt-get and find all the tools under /usr/lib/cmtk/bin, tried a few commands and it seems functioning. However, I cannot launch cmtk directly from terminal. Typing "cmtk" in bash pops a message "/usr/bin/cmtk: line 49: /usr/lib/cmtk/bin/: Is a directory". I have to enter the folder /usr/lib/cmtk/bin to access any function there. This may sound silly, but Is it possible to launch cmtk directly from terminal?

Best,
Dan