LESS - Installation

System Requirements for LESS

Operating System − Cross-platform
Browser Support − IE (Internet Explorer 8+), Firefox, Google Chrome, Safari.

Installation of LESS

Let us now understand the installation of LESS.

Step 1 − We need NodeJs to run LESS examples. To download NodeJs, open the link https://nodejs.org/en/, you will see a screen as shown below −

Dowload the Latest Features version of the zip file.

Step 2 − Run the setup to install the Node.js on your system.

Step 3 − Next, Install LESS on the server via NPM (Node Package Manager). Run the following command in the command prompt.

npm install -g less

Step 4 − After successful installation of LESS, you will see the following lines on the command prompt −

`-- less@2.6.1
   +-- errno@0.1.4
   | `-- prr@0.0.0
   +-- graceful-fs@4.1.3
   +-- image-size@0.4.0
   +-- mime@1.3.4
   +-- mkdirp@0.5.1
   | `-- minimist@0.0.8
   +-- promise@7.1.1
   | `-- asap@2.0.3
   +-- request@2.69.0
   | +-- aws-sign2@0.6.0
   | +-- aws4@1.3.2
   | | `-- lru-cache@4.0.0
   | |   +-- pseudomap@1.0.2
   | |   `-- yallist@2.0.0
   | +-- bl@1.0.3
   | | `-- readable-stream@2.0.6
   | |   +-- core-util-is@1.0.2
   | |   +-- inherits@2.0.1
   | |   +-- isarray@1.0.0
   | |   +-- process-nextick-args@1.0.6
   | |   +-- string_decoder@0.10.31
   | |   `-- util-deprecate@1.0.2
   | +-- caseless@0.11.0
   | +-- combined-stream@1.0.5
   | | `-- delayed-stream@1.0.0
   | +-- extend@3.0.0
   | +-- forever-agent@0.6.1
   | +-- form-data@1.0.0-rc4
   | | `-- async@1.5.2
   | +-- har-validator@2.0.6
   | | +-- chalk@1.1.1
   | | | +-- ansi-styles@2.2.0
   | | | | `-- color-convert@1.0.0
   | | | +-- escape-string-regexp@1.0.5
   | | | +-- has-ansi@2.0.0
   | | | | `-- ansi-regex@2.0.0
   | | | +-- strip-ansi@3.0.1
   | | | `-- supports-color@2.0.0
   | | +-- commander@2.9.0
   | | | `-- graceful-readlink@1.0.1
   | | +-- is-my-json-valid@2.13.1
   | | | +-- generate-function@2.0.0
   | | | +-- generate-object-property@1.2.0
   | | | | `-- is-property@1.0.2
   | | | +-- jsonpointer@2.0.0
   | | | `-- xtend@4.0.1
   | | `-- pinkie-promise@2.0.0
   | |   `-- pinkie@2.0.4
   | +-- hawk@3.1.3
   | | +-- boom@2.10.1
   | | +-- cryptiles@2.0.5
   | | +-- hoek@2.16.3
   | | `-- sntp@1.0.9
   | +-- http-signature@1.1.1
   | | +-- assert-plus@0.2.0
   | | +-- jsprim@1.2.2
   | | | +-- extsprintf@1.0.2
   | | | +-- json-schema@0.2.2
   | | | `-- verror@1.3.6
   | | `-- sshpk@1.7.4
   | |   +-- asn1@0.2.3
   | |   +-- dashdash@1.13.0
   | |   | `-- assert-plus@1.0.0
   | |   +-- ecc-jsbn@0.1.1
   | |   +-- jodid25519@1.0.2
   | |   +-- jsbn@0.1.0
   | |   `-- tweetnacl@0.14.1
   | +-- is-typedarray@1.0.0
   | +-- isstream@0.1.2
   | +-- json-stringify-safe@5.0.1
   | +-- mime-types@2.1.10
   | | `-- mime-db@1.22.0
   | +-- node-uuid@1.4.7
   | +-- oauth-sign@0.8.1
   | +-- qs@6.0.2
   | +-- stringstream@0.0.5
   | +-- tough-cookie@2.2.2
   | `-- tunnel-agent@0.4.2
   `-- source-map@0.5.3

Example

Following is a simple example of LESS.

hello.htm

<!doctype html>
   <head>
      <link rel = "stylesheet" href = "style.css" type = "text/css" />
   </head>
   
   <body>
      <h1>Welcome to Howcodex</h1>
      <h3>Hello!!!!!</h3>
   </body>
</html>

Let us now create a file style.less which is quite similar to CSS, the only difference is that it will be saved with .less extension. Both the files, .html and .less should be created inside the folder nodejs.

style.less

@primarycolor: #FF7F50;
@color:#800080;
h1 {
   color: @primarycolor;
}

h3 {
   color: @color;
}

Compile style.less file to style.css by using the following command −

lessc style.less style.css

When you run the above command, it will create the style.css file automatically. Whenever you change the LESS file, it's necessary to run the above command in the cmd and then the style.css file will get updated.

The style.css file will have the following code when you run the above command −

style.css

h1 {
  color: #FF7F50;
}

h3 {
  color: #800080;
}

Output

Let us now carry out the following steps to see how the above code works −

Save the above html code in the hello.htm file.
Open this HTML file in a browser, the following output will get displayed.

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