node.js - Change from child process exec to spawn dont work -

i use child process exec , need switch child process spawn

this working me.

var child = child_process.exec("npm install express --save" options, function (error, stdout, stderr) {     .....  }); 

when switch spawn doesnt work got error

var child = child_process.spawn("npm install express --save" options);   error: spawn npm enoent     @ exports._errnoexception (util.js:746:11)     @ process.childprocess._handle.onexit (child_process.js:1053:32)     @ child_process.js:1144:20 

i try var child = child_process.spawn("npm", ["install express --save"], options);

and doesnt work me, can issue?

i guess on windows environment.

so, have enter terminal , use commands want.

we see in node.js docs child_process.exec() method has spec in options default according operating system.

shell string shell execute command (default: '/bin/sh' on unix, 'cmd.exe' on windows, shell should understand -c switch on unix or /s /c on windows. on windows, command line parsing should compatible cmd.exe.)

so when using spawn, things changing.

var child = child_process.spawn("cmd",["/c","npm install express --save"], options); 

the above code block, starts new instance of windows command interpreter(cmd) , carries out command specified string , terminates(/c) , our specific command npm install express --save works on windows command interpreter.windows cmd commands references