Insert a "--" flag before the folder name. 'cd -- "-somedir-"' The "--" tells the command that there are no more options and everything follows it is an argument (usually a file or folder name).
And remember, when you have "illegal" characters in a filename (including spaces), they need to be be escaped by either enclosing the whole name in quotes or by placing a backslash in front of the illegal character.
Of course, the best thing is simply to not use illegal characters in pathnames in the first place.
