I'm currently building a MC map and wanted to add an item to the 5th slot there by command. I know how to do that and have done that before, but forgot the command. I play Minecraft in the 1.8.
In the latest version, this is:
/ replaceitem entity @p hotbar.4 minecraft: emerald
Whether that is synonymous in the 1.8 I do not know for sure… But so about it would have to be, otherwise just look for / replaceitem!
Hope that helps you!
Why 1.8? This is mega lame and missing thousands of features.
^ I can only confirm