I was in OSX's terminal yesterday trying to cd into a folder with a space in the name. That usually works really well with tab-completion but in the same place in the directory tree there were another folder with the same name but without the space.
Here's a little illustration to clarify what I just wrote.
+--Folder1 With Space
So I want to cd into "Folder1 With Space" but I can't use tab-completion or type:
cd Folder1 With Space
However I can use \ as the escape character:
cd Folder1\ With\ Space
I can also use quotes, 'normal' or "double" (useful if the folder uses either one in it's name).
cd 'Folder1 With Space'
cd "Folder1 With Space"
Although I haven't tried it I'm pretty sure this works in any *nix terminal.