Table of Contents

System

This module implement a equivalent to the Unix system command. It is a simplified alternative to the process module for spawning and getting the result of an external command.

Use require( hop.system ) or ` from "hop:system"` to use it.* import

Functions

system.system( command )

Spawn process of executing command. Command might either be a string or a array of strings. The result is a promise that resolves if the execution succeeds, i.e., if its return code is 0, and rejects otherwise. On resolution, the output the process has generated is the value of the resolution. On rejection, the value is an object of two fields:

Strings are converted into array of strings using the following function:

function stringToCmd( cmd ) {
   return cmd
      .match( /([^ "']+)|"([^"]*)"|'([^']*)'|(?:[ \t]+)/g )
      .filter( s => !s.match( /^[ \t]+$/ ) )
      .map( s => s[ 0 ] === "'" || s[ 0 ] === '"'
               ? s.substring( 1, s.length - 1 )
               : s );
}

That is:

"foo" -> [ 'foo' ]
"foo bar" -> [ 'foo', 'bar' ]
"foo bar gee" -> [ 'foo', 'bar', 'gee' ]
'foo "bar gee" hux' -> [ 'foo', 'bar gee', 'hux' ]

system.systemSync( command )

The synchronous, i.e. blocking, version of system.system. It spawns a process of executing command. Command might either be a string or a array of strings. The result is an object with two fields:

Example

This example shows how to spawn an external process and get the result in a string.

system/system.js

import { systemSync as system } from hop.system;

const { status, data } = system( "ls -l /tmp" );

if( status ) {
   console.log( "error", status, data );
} else {
   console.log( data.split() );
}