Possible commands

You can execute an editor command by pressing Ctrl-e followed by the command. Here are the possible commands that you can use.

quit: Quits micro.
save: Saves the current buffer.
replace "search" "value" flags: This will replace search with value. The flags are optional. At this point, there is only one flag: c, which enables check mode which asks if you'd like to perform the replacement each time

Note that search must be a valid regex. If one of the arguments does not have any spaces in it, you may omit the quotes.
set option value: sets the option to value. See the options help topic for a list of options you can set.
setlocal option value: sets the option to value locally (only in the current buffer).
show option: shows the current value of the given option.
run sh-command: runs the given shell command in the background. The command's output will be displayed in one line when it finishes running.
bind key action: creates a keybinding from key to action. See the sections on keybindings above for more info about what keys and actions are available.
vsplit filename: opens a vertical split with filename. If no filename is provided, a vertical split is opened with an empty buffer
hsplit filename: same as vsplit but opens a horizontal split instead of a vertical split
tab filename: opens the given file in a new tab.

The following commands are provided by the default plugins: