rc

Start an interactive rc shell

$ rc

$ rc [script.rc]

$ rc -c '[command]'

$ rc -n

$ rc -l

rc [-einvxl] [-c command] [file [arguments]]

rc is the Plan 9 command interpreter, offering a cleaner alternative to the Bourne shell. Originally designed for Plan 9 from Bell Labs, it has been ported to Unix systems and provides a simpler, more consistent syntax.
Unlike the Bourne shell's string variables, rc provides list-valued variables (arrays of strings) as a fundamental type. This eliminates many quoting problems and makes argument handling more natural.
Rc uses C-like syntax for control structures: if, while, for, switch, and fn for function definitions. The syntax is defined by a formal grammar (implemented with yacc), making it unambiguous and predictable.
Pipes, redirections, and command substitution work similarly to other shells. Background execution uses &, and command grouping uses {} instead of subshells.

-c command

Execute the given command string and exit

Exit if any command returns non-zero status

Run interactively (read commands from terminal)

Behave as a login shell (read profile)

Do not read the personal profile ($home/lib/profile)

Echo input to standard error as it is read

Print commands and arguments as they are executed

Variables: `var=value` becomes `var=value` (same), but `$var` expands to a list
Lists: `list=(a b c)` defines a list, accessed as `$list(1)`, `$list(2)`, etc.
Functions: `fn name { commands }` instead of `name() { commands }`
If/else: `if(test) cmd` and `if not cmd` or `else cmd`
For loop: `for(i in list) cmd`
Quoting: Single quotes only, doubled to include literal quote: `'it''s'`

Rc is not POSIX-compatible. Scripts written for bash or sh will not run correctly in rc without modification.
The Unix ports (Rakitzis implementation and Plan 9 from User Space) have slight differences from the original Plan 9 rc, particularly in profile locations and some features.
Limited availability in default package repositories. May require building from source or installing Plan 9 ports.

Rc was created by Tom Duff at Bell Labs in 1989 for the Research Unix Version 10 and later became the standard shell for Plan 9. The name stands for "run commands." Byron Rakitzis created a popular Unix reimplementation in 1991, which continues to be maintained. Duff is also known for "Duff's device," an optimization technique in C.

sh(1), bash(1), zsh(1), es(1)