command
Execute a command bypassing shell built-ins
TLDR
Execute the ls program literally, even if an ls alias exists
Find and execute a command using a default $PATH (/bin:/usr/bin:/sbin:/usr/sbin:/etc:/usr/etc) that guarantees to find all standard utilities
Display the path to the executable or the alias definition of a specific command
SYNOPSIS
command [-pVv] command [arg ...]
command [-p] command-name
command -pVv
PARAMETERS
-p
Use default PATH for standard utilities
-V
Print version description of command
-v
Print path or description of command
DESCRIPTION
command is a shell builtin in Bash and other POSIX shells that executes the specified command, ignoring any shell function with the same name. This prevents custom functions from overriding standard utilities or builtins, ensuring the intended program runs. For example, if a function named grep exists, grep pattern file calls the function, but command grep pattern file invokes the system's grep.
The -p option uses a default PATH (typically /usr/bin:/bin:/usr/sbin:/sbin) to locate standard utilities, enhancing script portability without depending on user PATH settings. -v prints the path or description of the command (e.g., builtin or file), while -V shows version information. These are invaluable for debugging and verification in scripts.
As a POSIX-standard feature, command promotes reliable scripting across environments. It searches PATH for non-builtins and functions only as a last resort after options. Exit status matches the invoked command or indicates errors like command not found (127). Widely used in makefiles, init scripts, and automation to avoid function interference.
CAVEATS
command bypasses functions but not aliases; escape with \ or quote to ignore aliases. POSIX-compliant but shell-specific behavior may vary.
EXAMPLES
command ls # Ignores ls function, runs binary
command -v ls # /bin/ls
command -p grep foo # Uses default PATH
command -V echo # echo: shell builtin
EXIT STATUS
0 if command succeeds; 126 if not executable; 127 if not found; 1+ on errors.
HISTORY
Originated in early Bourne shell derivatives like ksh; standardized in POSIX.1-2008 for portability. Bash includes it since version 1.0 (1989), with refinements for builtins and PATH handling.
