NPM Install the difference between a local installation and a global installation

NPM's package installation is divided into local installation (locals), global installation (globally), and from the command line, the difference is just that there is no-G, such as

NPM Install Grunt # Local Installation

NPM install-g GRUNT-CLI # Global Installation

What's the difference between the two installation methods? The main difference, as illustrated in the NPM official documentation, is the following 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. Put the installation package under/usr/local

2. Can be used directly in the command line

Local Installation

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

Like running the following command

NPM Install grunt--save-dev

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

Casperchenmacbookpro:testusemin casperchen$ LL

Total 200

Drwxr-xr-x Casperchen staff 544B 23:17 node_modules

Enter Node_modules

Casperchenmacbookpro:node_modules casperchen$ LL

Total 0

Drwxr-xr-x Casperchen Staff 544B 5 00:49 Grunt

2, can be introduced by require () to install the local package

As a direct example, we create test.js in the project root directory, which is very simple

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

Then run Test.js on the console

Node Test.js

Then you'll see the following output

Casperchenmacbookpro:testusemin casperchen$ Node Test.js

Hello Grunt

Global Installation

1, put 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 find that GRUNT-CLI has been placed underneath.

Casperchenmacbookpro:bin casperchen$ pwd

/usr/local/bin

Casperchenmacbookpro:bin casperchen$ ll Grunt

Lrwxr-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/,/usr/local/bin executable file is only soft link

2, can be used directly in the command line

Implementation details are actually mentioned above, by creating a soft link under '/usr/local/bin. Don't repeat it here.

A more intuitive example

Let's look directly at what happens when we run the grunt task in the project directory (the task is a specific grunt name and replace it yourself). Here we have to use Node-inspector.

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

Run the following command to turn on debugging

Node-inspector &

See the following output

Casperchenmacbookpro:tmp casperchen$ Node-inspector &

[1] 14390

Casperchenmacbookpro:tmp casperchen$ Node Inspector v0.6.1

Info-socket.io started

Visit 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) dev

Debugger 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. The tips shown from the side can be seen, the global command grunt is actually/usr/local/lib/node_modules/grunt-cli/bin/grunt

Press F8 and then run down, and it will go into the gruntfile.js, where the grunt is a locally installed node package. The global command is as confusing as the local package name.