rush-builtins - builtin commands provided by Rush
Builtins are commands executed by Rush itself instead of by searching PATH. POSIX builtins are part of the shell core. Compatibility and Rush-specific builtins are extension builtins included by the default Rush registry.
Embedders may provide their own extension builtin registry. Extension builtins are regular builtins; POSIX special builtin behavior is reserved for the shell core.
Rush provides the POSIX special builtin names. Special builtins are found before shell functions and have POSIX-defined error and assignment semantics.
:- Return success without doing anything.
.- Read and execute commands from a file in the current shell environment.
break- Exit enclosing
for, while, or until loops.
continue- Continue enclosing
for, while, or until loops.
eval- Concatenate arguments and evaluate the result as shell input.
exec- Replace the shell with a command, or apply redirections to the current shell.
exit- Exit the shell.
export- Mark variables for export to child process environments.
readonly- Mark variables as readonly.
return- Return from a function or sourced script.
set- Set shell options and positional parameters.
shift- Shift positional parameters.
times- Print accumulated shell and child process times.
trap- Register commands to run when signals are received.
unset- Unset variables or functions.
Rush also provides POSIX regular builtin names. Regular builtins follow normal command lookup order and may be shadowed by functions.
[- Evaluate a conditional expression; synonym for
test requiring a closing ].
alias- Define or print command aliases.
bg- Resume jobs in the background.
cd- Change the current working directory.
command- Execute or describe a command while suppressing shell function lookup.
echo- Write arguments to standard output.
env- Run a command with a modified environment, or print the environment.
false- Return an unsuccessful status.
fc- List or edit command history.
fg- Resume jobs in the foreground.
getopts- Parse shell function option arguments.
hash- Remember or report command path lookups.
jobs- Report active jobs.
kill- Send signals to processes or jobs.
printf- Format and write data.
pwd- Print the current working directory.
read- Read a line and assign fields to variables.
test- Evaluate a conditional expression.
true- Return a successful status.
ulimit- Get or set process resource limits.
umask- Get or set the file mode creation mask.
unalias- Remove command aliases.
wait- Wait for jobs or process IDs to complete.
Compatibility builtins are non-POSIX extension builtins included by the default Rush registry because they are common in interactive shell configuration and portable shell-adjacent scripts.
local- Declare variables local to the current function invocation.
shopt- Inspect or update compatibility shell options.
source- Read and execute commands from a file in the current shell environment.
type- Describe how command names would be resolved.
Rush-specific builtins expose interactive shell features through normal shell commands.
abbr- Manage fish-style interactive abbreviations.
color- Derive
#rrggbb colors for prompt and UI style configuration.
prompt- Append styled text while rendering the interactive prompt.
prompt_async- Return cached prompt command output and refresh it in the background.
prompt_duration- Print the previous foreground command duration for prompt rendering.
prompt_pwd- Print a prompt-friendly current directory.
rush configuration, rush compatibility notes, POSIX Shell Command Language.