you can use the apt group of commands or aptitude which i recommend above apt. Here is the list to search
APT
To search for something similar to the command you want:
apt-cache search X
for example apt-cache search cheese
will give you everything related to cheese.
To show what dependencies and stuff it has you would do apt-cache show cheese
.
Of course to install would be apt-get install cheese
.
APTITUDE
To search: aptitude search cheese
which will show a more nicer list than apt
To show: aptitude show cheese
which again will show a more nicer and friendlier list
To install: aptitude install cheese
to install it. Again nicer.
Also aptitude gives more relevant information to what you are looking for, for example:
apt-cache search phi
VS aptitude search phi
apt-cache search sphi
VS aptitude search sphi
If you want a GUI version i recommend Synaptic Package Manager or a simpler Software Center. In Synaptic you can look for something similar to what you are looking for and it will show it to you.