[Go] npm install local installation differs from global installation

NPM package installation is divided into local installation (locally), the global installation of two, from the command line to see, the difference is only G, such as

NPM Install Grunt # Local installation NPM install-g GRUNT-CLI # Global Installation

What is the difference between these two types of installation? From the description of the NPM official documentation, the main difference is (explained later by specific examples):
Local Installation
1. Place the installation package under./node_modules (the directory where NPM is running)
2. A locally installed package can be introduced via require ()

Global Installation
1. Place the installation package under/usr/local
2. Can be used directly on the command line

Local Installation

1. Place the installation package under the./node_modules (the directory where NPM is running)

For example, run the following command

NPM Install grunt--save-dev

Then, you will find a node_modules directory in the current directory, you can see grunt this package

Casperchenmacbookpro:testusemin casperchen$ lltotal 200drwxr-xr-x casperchen staff 544B 23:17 node_modules

Enter Node_modules

Casperchenmacbookpro:node_modules casperchen$ lltotal 0drwxr-xr-x casperchen staff 544B 5 00:49 Grunt

2. The locally installed package can be introduced via require ()

Just for example, we create test.js under the project root, which is very simple

var grunt = require (' grunt '); Grunt.log.writeln (' Hello Grunt ');

Then run Test.js on the console

Node Test.js

You will then see the following output

Casperchenmacbookpro:testusemin casperchen$ node Test.js Hello Grunt

Global Installation

1. Place the installation package under the/usr/local

Run the following command

NPM install-g GRUNT-CLI

Then go into the/usr/local/bin directory and you'll see that GRUNT-CLI is already placed below.

Casperchenmacbookpro:bin casperchen$ pwd/usr/local/bincasperchenmacbookpro:bin casperchen$ ll gruntlrwxr-xr-x 1 root Admin 39B 8 21:43 grunt. /lib/node_modules/grunt-cli/bin/grunt

Visible, the real installation path of the global module under/usr/local/lib/node_modules/, the executable file under/usr/local/bin is just a soft link.

2, can be directly used in the command line

Implementation details are described above, and are implemented by creating a soft link under '/usr/local/bin '. I don't repeat it here.

More intuitive examples

Here's a look at what happens when we run the Grunt task (task for a specific grunt task name and replace it yourself) in the project directory. The node-inspector is here to help.

First of all, no contact with node-inspector children's shoes can refer to the previous article to understand the following

Run the following command to turn on debugging

Node-inspector &

See the output below

Casperchenmacbookpro:tmp casperchen$ node-inspector &[1] 14390casperchenmacbookpro:tmp casperchen$ node Inspector v0.6.1 Info-socket.io startedvisit http://127.0.0.1:8080/debug?port=5858 to start debugging.

Next, run the grunt task under the current task

^ccasperchenmacbookpro:testusemin casperchen$ node--debug-brk $ (which grunt) Devdebugger listening on port 5858

Then, open the Chrome browser, enter the URL http://127.0.0.1:8080/debug?port=5858, will automatically enter the breakpoint debugging state. As you can see from the tips shown on the side, the global command grunt is actually/usr/local/lib/node_modules/grunt-cli/bin/grunt

Press F8 and then run down, will enter as Gruntfile.js, at this time the grunt, is a local installation of a node package. The global command, like the local package name, is quite confusing.

[Go] npm install local installation differs from global installation