The equivalent you are looking for is xdg-open, which can be used in the same way as OS X's open command. For example:
xdg-open ~/Documents/Chubby_Bubbies.odt
However, this is really hard to type quickly and accurately. Instead, you should make an alias to xdg-open, which makes the process much quicker.
Of course, you can alias it to open to make it match OS X (you can pick anything you want), but personally, I use the right square bracket (]) for my shortcut for speed reasons. To use this, add the following to your .bashrc file:
alias ']'='xdg-open'
Then, to open any resource, use it like any of these examples:
] www.google.com
] file.txt
] ~/Pictures
] ssh://myserver.local/home/jeremy
Also this lets you open a file browser (e.g. Nautilus) in the current directory:
] .
From experience I have found that one-letter aliases work best for the above shortcut. After all, the goal is efficiency. And you can go back and make the same alias on OS X — I leave that as an exercise to the reader. :-)
