Execute a command line binary with Node js

Question

I am in the process of porting a CLI library from Ruby over to Node js  In my code I execute several third party binaries when necessary  I am not sure how best to accomplish this in Node   Here s an example in Ruby where I call PrinceXML to convert a file to a PDF   cmd   system  prince -v builds pdf book html -o builds pdf book pdf     What is the equivalent code in Node

User · Answer

Node JS v15 8 0  LTS v14 15 4  and v12 20 1  ---  Feb 2021 Async method  Unix    use strict    const   spawn     require   child process     const ls   spawn   ls      -lh     usr        ls stdout on   data     data     gt        console log   stdout     data             ls stderr on   data     data     gt        console log   stderr     data             ls on   close     code     gt        console log   child process exited with code    code              Async method  Windows    use strict    const   spawn     require   child process        NOTE  Windows Users  this command appears to be differ for a few users     You can think of this as using Node to execute things in your Command Prompt     If  cmd  works there  it should work here     If you have an issue  try  dir      const dir   spawn   dir              const dir   spawn   cmd       c    dir        dir stdout on   data     data     gt  console log   stdout     data         dir stderr on   data     data     gt  console log   stderr     data         dir on   close     code     gt  console log   child process exited with code   code          Sync   use strict    const   spawnSync     require   child process     const ls   spawnSync   ls      -lh     usr        console log   stderr     ls stderr toString         console log   stdout     ls stdout toString          From Node js v15 8 0 Documentation The same goes for Node js v14 15 4 Documentation and Node js v12 20 1 Documentation

User · Answer

const exec   require  child process   exec exec  ls    error  stdout  stderr    gt       do whatever here

User · Answer

If you don t mind a dependency and want to use promises  child-process-promise works   installation  npm install child-process-promise --save   exec Usage  var exec   require  child-process-promise   exec   exec  echo hello        then function  result            var stdout   result stdout          var stderr   result stderr          console log  stdout     stdout           console log  stderr     stderr               catch function  err            console error  ERROR     err             spawn usage  var spawn   require  child-process-promise   spawn   var promise   spawn  echo     hello      var childProcess   promise childProcess   console log   spawn  childProcess pid     childProcess pid   childProcess stdout on  data   function  data        console log   spawn  stdout     data toString         childProcess stderr on  data   function  data        console log   spawn  stderr     data toString          promise then function              console log   spawn  done                 catch function  err            console error   spawn  ERROR     err

User · Answer

Use this lightweight npm package  system-commands  Look at it here   Import it like this   const system   require  system-commands     Run commands like this   system  ls   then output   gt        console log output     catch error   gt        console error error

User · Answer

You are looking for child process exec  Here is the example   const exec   require  child process   exec  const child   exec  cat   js bad file   wc -l        error  stdout  stderr    gt            console log  stdout    stdout             console log  stderr    stderr             if  error     null                console log  exec error    error

User · Answer

Now you can use shelljs   from node v4   as follows    var shell   require  shelljs     shell echo  hello world    shell exec  node --version

User · Answer

I just wrote a Cli helper to deal with Unix windows easily   Javascript   define   require    exports    function  require  exports                   Helper to use the Command Line Interface  CLI  easily with both Windows and Unix environments         Requires underscore or lodash as global through                  var Cli    function              function Cli                                     Execute a CLI command                 Manage Windows and Unix environment and try to execute the command on both env if fails                 Order  Windows - gt  Unix                                 param command                   Command to execute    grunt                   param args                      Args of the command    watch                   param callback                  Success                  param callbackErrorWindows      Failure on Windows env                  param callbackErrorUnix         Failure on Unix env                          Cli execute   function  command  args  callback  callbackErrorWindows  callbackErrorUnix                if  typeof args      undefined                     args                                 Cli windows command  args  callback  function                      callbackErrorWindows                     try                       Cli unix command  args  callback  callbackErrorUnix                     catch  e                        console log  ------------- Failed to perform the command       command      on all environments  -------------                                                                         Execute a command on Windows environment                         param command       Command to execute    grunt               param args          Args of the command    watch               param callback      Success callback              param callbackError Failure callback                      Cli windows   function  command  args  callback  callbackError                if  typeof args      undefined                     args                                 try                   Cli  execute process env comspec    union    c   command   args                    callback command  args   Windows                  catch  e                    callbackError command  args   Windows                                                     Execute a command on Unix environment                         param command       Command to execute    grunt               param args          Args of the command    watch               param callback      Success callback              param callbackError Failure callback                      Cli unix   function  command  args  callback  callbackError                if  typeof args      undefined                     args                                 try                   Cli  execute command  args                   callback command  args   Unix                  catch  e                    callbackError command  args   Unix                                                     Execute a command no matters what s the environment                         param command   Command to execute    grunt               param args      Args of the command    watch               private                     Cli  execute   function  command  args                var spawn   require  child process   spawn              var childProcess   spawn command  args                childProcess stdout on  data   function  data                    console log data toString                                  childProcess stderr on  data   function  data                    console error data toString                                        return Cli                exports Cli   Cli        Typescript original source file           Helper to use the Command Line Interface  CLI  easily with both Windows and Unix environments     Requires underscore or lodash as global through          export class Cli                   Execute a CLI command         Manage Windows and Unix environment and try to execute the command on both env if fails         Order  Windows - gt  Unix                 param command                   Command to execute    grunt           param args                      Args of the command    watch           param callback                  Success          param callbackErrorWindows      Failure on Windows env          param callbackErrorUnix         Failure on Unix env              public static execute command  string  args  string         callback     any  callbackErrorWindows     any  callbackErrorUnix     any            Cli windows command  args  callback  function                  callbackErrorWindows                 try                   Cli unix command  args  callback  callbackErrorUnix                 catch  e                    console log  ------------- Failed to perform the command       command      on all environments  -------------                                                    Execute a command on Windows environment                 param command       Command to execute    grunt           param args          Args of the command    watch           param callback      Success callback          param callbackError Failure callback              public static windows command  string  args  string         callback     any  callbackError     any            try               Cli  execute process env comspec    union    c   command   args                callback command  args   Windows              catch  e                callbackError command  args   Windows                                    Execute a command on Unix environment                 param command       Command to execute    grunt           param args          Args of the command    watch           param callback      Success callback          param callbackError Failure callback              public static unix command  string  args  string         callback     any  callbackError     any            try               Cli  execute command  args               callback command  args   Unix              catch  e                callbackError command  args   Unix                                    Execute a command no matters what s the environment                 param command   Command to execute    grunt           param args      Args of the command    watch           private             private static  execute command  args            var spawn   require  child process   spawn          var childProcess   spawn command  args            childProcess stdout on  data   function  data                console log data toString                          childProcess stderr on  data   function  data                console error data toString                          Example of use       Cli execute Grunt  command  args  function  command  args  env            console log  Grunt has been automatically executed       env                 function  command  args  env            console error  ------------- Windows      command      command failed  trying Unix    ---------------            function  command  args  env            console error  ------------- Unix      command      command failed too  ---------------

User · Answer

hexacyanide s answer is almost a complete one   On Windows command prince could be prince exe  prince cmd  prince bat or just prince  I m no aware of how gems are bundled  but npm bins come with a sh script and a batch script - npm and npm cmd   If you want to write a portable script that would run on Unix and Windows  you have to spawn the right executable   Here is a simple yet portable spawn function   function spawn cmd  args  opt        var isWindows    win  test process platform        if   isWindows             if    args   args               args unshift cmd           args unshift   c            cmd   process env comspec             return child process spawn cmd  args  opt      var cmd   spawn  prince     -v    builds pdf book html    -o    builds pdf book pdf        Use these props to get execution results     cmd stdin     cmd stdout     cmd stderr

User · Answer

If you want something that closely resembles the top answer but is also synchronous then this will work   var execSync   require  child process   execSync  var cmd    echo  hello world     var options       encoding   utf8      console log execSync cmd  options

User · Answer

For even newer version of Node js  v8 1 4   the events and calls are similar or identical to older versions  but it s encouraged to use the standard newer language features  Examples   For buffered  non-stream formatted output  you get it all at once   use child process exec   const   exec     require  child process    exec  cat   js bad file   wc -l    err  stdout  stderr    gt      if  err           node couldn t execute the command     return            the  entire  stdout and stderr  buffered    console log  stdout    stdout       console log  stderr    stderr           You can also use it with Promises   const util   require  util    const exec   util promisify require  child process   exec    async function ls       const   stdout  stderr     await exec  ls      console log  stdout    stdout     console log  stderr    stderr     ls      If you wish to receive the data gradually in chunks  output as a stream   use child process spawn   const   spawn     require  child process    const child   spawn  ls     -lh     usr         use child stdout setEncoding  utf8    if you want text chunks child stdout on  data    chunk    gt         data from standard output is here as buffers         since these are streams  you can pipe them elsewhere child stderr pipe dest    child on  close    code    gt      console log  child process exited with code   code           Both of these functions have a synchronous counterpart  An example for child process execSync   const   execSync     require  child process       stderr is sent to stderr of parent process    you can set options stdio if you want it to go elsewhere let stdout   execSync  ls      As well as child process spawnSync   const   spawnSync    require  child process    const child   spawnSync  ls     -lh     usr      console log  error   child error   console log  stdout    child stdout   console log  stderr    child stderr       Note  The following code is still functional  but is primarily targeted at users of ES5 and before   The module for spawning child processes with Node js is well documented in the documentation  v5 0 0   To execute a command and fetch its complete output as a buffer  use child process exec   var exec   require  child process   exec  var cmd    prince -v builds pdf book html -o builds pdf book pdf    exec cmd  function error  stdout  stderr         command output is in stdout       If you need to use handle process I O with streams  such as when you are expecting large amounts of output  use child process spawn   var spawn   require  child process   spawn  var child   spawn  prince        -v    builds pdf book html      -o    builds pdf book pdf       child stdout on  data   function chunk         output will be here in chunks         or if you want to send output elsewhere child stdout pipe dest     If you are executing a file rather than a command  you might want to use child process execFile  which parameters which are almost identical to spawn  but has a fourth callback parameter like exec for retrieving output buffers  That might look a bit like this   var execFile   require  child process   execFile  execFile file  args  options  function error  stdout  stderr         command output is in stdout         As of v0 11 12  Node now supports synchronous spawn and exec  All of the methods described above are asynchronous  and have a synchronous counterpart  Documentation for them can be found here  While they are useful for scripting  do note that unlike the methods used to spawn child processes asynchronously  the synchronous methods do not return an instance of ChildProcess

User · Answer

Since version 4 the closest alternative is child process execSync method  const  execSync    require  child process     let output   execSync  prince -v builds pdf book html -o builds pdf book pdf         Note that execSync call blocks event loop

[javascript] Execute a command line binary with Node.js

Node JS `v15.8.0`, LTS `v14.15.4`, and `v12.20.1` --- Feb 2021

Examples related to javascript

Examples related to ruby

Examples related to node.js

Examples related to command-line-interface