This question (How can I remove gnome from a kubuntu 12.04 install?) have the commands with question markes:
sudo apt-get remove --purge ubuntu-desktop
sudo apt-get remove --purge unity?
sudo apt-get remove --purge gnome?
What do they mean?
Those are called Wildcards (globbing patterns)
Standard wildcards (also known as globbing patterns) are used by various command-line utilities to work with multiple files.
Standard wildcards are used by nearly any command (including mv, cp, rm and many others).
(question mark)
this can represent any single character. If you specified something at the command line like "hd?" GNU/Linux would look for hda, hdb, hdc and every other letter/number between a-z, 0-9.
*(asterisk)
this can represent any number of characters (including zero, in other words, zero or more characters). If you specified a "cd*" it would use "cda", "cdrom", "cdrecord" and anything that starts with “cd” also including “cd” itself. "m*l" could by mill, mull, ml, and anything that starts with an m and ends with an l.
[ ] (square brackets)
specifies a range. If you did m[a,o,u]m it can become: mam, mum, mom if you did: m[a-d]m it can become anything that starts and ends with m and has any character a to d inbetween. For example, these would work: mam, mbm, mcm, mdm. This kind of wildcard specifies an “or” relationship (you only need one to match).
{ } (curly brackets)
terms are separated by commas and each term must be the name of something or a wildcard. This wildcard will copy anything that matches either wildcard(s), or exact name(s) (an “or” relationship, one or the other).
For example, this would be valid:
cp {.doc,.pdf} ~
This will copy anything ending with .doc or .pdf to the users home directory. Note that spaces are not allowed after the commas (or anywhere else).
[!]
This construct is similar to the [ ] construct, except rather than matching any characters inside the brackets, it'll match any character, as long as it is not listed between the [ and ]. This is a logical NOT. For example rm myfile[!9] will remove all myfiles* (ie. myfiles1, myfiles2 etc) but won't remove a file with the number 9 anywhere within it's name.
(backslash)
is used as an "escape" character, i.e. to protect a subsequent special character. Thus, "” searches for a backslash. Note you may need to use quotation marks and backslash(es).
for more examples: visit this page
