In Ubuntu 14.04 using Gnome Terminal 3.6.2
Free Mono:

Fira Code:

Also when I type two spaces followed by two greater than symbols I get two rightward pointing arrows until I switch windows, at which point it converts to:

I'm guessing this is also related to the same issue that I'm also seeing: #162
Using Fira Code in Atom editor doesn't appear to have any of the same issues. If there is any more information I can get you, let me know.
I believe this is because Gnome Terminal doesn't support ligatures: https://bugzilla.gnome.org/show_bug.cgi?id=762832
I'm not sure if there is a resolution to this issue from the font side, I'll leave it up to you to close this issue if there are no workarounds besides "use another font" :)
I鈥檓 afraid I can鈥檛 do anything about that
@hatched You could use the base Fira mono https://fonts.google.com/specimen/Fira+Mono
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@hatched You could use the base Fira mono https://fonts.google.com/specimen/Fira+Mono