# orca-c > A C-port of the ORCA live programming environment. > ORCA is an esoteric programming language for creating procedural sequencers. > More information: . - Start ORCA with an empty workspace: `orca-c` - Start ORCA and open a specific file: `orca-c {{path/to/file.orca}}` - Start ORCA and set a specific tempo (defaults to 120): `orca-c --bpm {{beats_per_minute}}` - Start ORCA and set the size of the grid: `orca-c --initial-size {{columns}}x{{rows}}` - Start ORCA and set the maximum number of undo steps (defaults to 100): `orca-c --undo-limit {{limit}}` - Show the main menu inside of ORCA: `F1` - Show all shortcuts inside of ORCA: `?` - Show all ORCA operators inside of ORCA: ` + g`