exec

The exec module is used to run external commands.

Like the underlying Go os/exec package, this module does not invoke the system shell, expand glob patterns, or handle other shell features.

Callable

The exec module itself is callable, using one of two signatures. The preferred form is now:

Function signature

exec(args []string, opts map) result

The old form that is still supported for backwards compatibility is:

Function signature

exec(name string, args []string, opts map) result

This provides a shorthand way to build and run a command. The function returns a result object containing the stdout and stderr produced by running the command. The opts argument is optional.

Example

>>> exec(["echo", "TEST"]).stdout
byte_slice("TEST\n")

The opts argument may be a map containing any of the following keys:

Name	Type	Description
dir	string	The working directory of the command.
env	map	The environment given to the command.
stdin	string, byte_slice, or reader	The standard input given to the command.
stdout	writer	The standard output destination.
stderr	writer	The standard error destination.

Functions

command

Two signatures are supported for the command function. The preferred form is now:

Function signature

command(args []string) command

The old form that is still supported for backwards compatibility is:

Function signature

command(name string, args ...string) command

Creates a new command with the given name and arguments. The command can then be executed with its run, start, output, or combined_output methods. Before the command is run, its path, dir, and env attributes may be set. Read more about the command type below.

Example

>>> exec.command(["echo", "TEST"]).output()
byte_slice("TEST\n")

look_path

Function signature

look_path(name string) string

Searches for the named executable in the directories contained in the PATH environment variable. If the name contains a slash, it is tried directly, without consulting the PATH. Otherwise, the result is the absolute path to the named executable.

Example

>>> exec.look_path("echo")
"/bin/echo"

Types

command

Represents an external command that is being built and run.

Attributes

Name	Type	Description
path	string	The path to the executable.
dir	string	The working directory of the command.
env	[]string	The environment given to the command.
stdout	byte_slice	The standard output produced by the command.
stderr	byte_slice	The standard error produced by the command.
run	func()	Runs the command and waits for it to complete.
output	func() byte_slice	Runs the command and returns its standard output.
combined_output	func() byte_slice	Runs the command and returns its combined standard output and standard error.
start	func()	Starts the command but does not wait for it to complete.
wait	func()	Waits for the command to exit.

Examples

Example

>>> c := exec.command("pwd")
>>> c.dir = "/dev"
>>> c.run()
>>> c.stdout
"/dev\n"

result

Represents the result of running an external command.

Attributes

Name	Type	Description
stdout	byte_slice	The standard output produced by the command.
stderr	byte_slice	The standard error produced by the command.
pid	int	The process ID of the command.

Examples

Example

>>> result := exec("ls")
>>> result.stdout
"file1\nfile2\n"

errors filepath