All players start with one backpack in addition to the normal inventory built into Rust. This backpack does not drop on death except in PVP environments. Additional backpack slots are available via skills. Backpacks also have the very useful yet underappreciated ability to allow players to bind keys to fetch specific items and specific quantities straight from their backpack to their hotbar.
Chat commands:/backpack - Open your backpack
/backpackgui - Toggle the backpack GUI button
Console commands:backpack - Open your backpack. If you have more than one page of backpack slots this command will also cycle through them.
backpack.open - Alternative command to open your backpack. If you have more than one page of backpack slots this command will also cycle through them.
backpack.fetch <item shortname> <amount> - take the set amount of items from your backpack to your hotbar (or inventory if unable to move to hotbar)
Keybind Samples:In game press F1 to open your console. You can copy and paste the keybinds below into that console or type your own. You can use any key in place of the [b] and [f] keys in the examples below.
bind b backpack - Will bind opening/cycling your backpack to [b] on your keyboard
bind b backpack.open - Will bind opening/cycling your backpack to [b] on your keyboard
bind f backpack.fetch explosive.timed 2 - This will bring two C4 from your backpack to your hotbar each time you press it.