npm install less -g

npm install less@1.6.2 -g

Usage: lessc [option option=parameter ...] <source> [destination]

E:\Dev\Dev2015\less compile dir>lessc bootstrap.less bootstrap.css

lessc -x bootstrap.less bootstrap.css

lessc --help

lessc -h

 -M, --depends            Outputs a makefile import dependency list to stdout.

--no-color               Disables colorized output.

--no-ie-compat           Disables IE compatibility checks.

--no-js                  Disables JavaScript in less files

-l, --lint               Syntax check only (lint).

-s, --silent             Suppresses output of error messages.

 --strict-imports         Forces evaluation of imports.

 --insecure               Allows imports from insecure https hosts.

--plugin=PLUGIN=OPTIONS  Loads a plugin. You can also omit the --plugin= if the plugin beginsless-plugin. E.g. the clean css plugin is called less-plugin-clean-cssonce installed (npm install less-plugin-clean-css), use either with--plugin=less-plugin-clean-css or just --clean-cssspecify options afterwards e.g. --plugin=less-plugin-clean-css="advanced"or --clean-css="advanced"

PS E:\Dev\Dev2015\less compile dir> npm install less-plugin-clean-css
less-plugin-clean-css@1.5.0 node_modules\less-plugin-clean-css
└── clean-css@3.1.2 (commander@2.6.0, source-map@0.1.43)
PS E:\Dev\Dev2015\less compile dir>

lessc --plugin=less-plugin-clean-css .\bootstrap.less bootstrap.css

 -v, --version            Prints version number and exit.

 --source-map[=FILENAME]  Outputs a v3 sourcemap to the filename (or output filename.map).--source-map-rootpath=X  Adds this path onto the sourcemap filename and less file paths.--source-map-basepath=X  Sets sourcemap base path, defaults to current working directory.--source-map-less-inline Puts the less files into the map instead of referencing them.--source-map-map-inline  Puts the map (and any less files) as a base64 data uri into the output css file.--source-map-url=URL     Sets a custom URL to map file, for sourceMappingURL commentin generated CSS file.-rp, --rootpath=URL      Sets rootpath for url rewriting in relative imports and urlsWorks with or without the relative-urls option.-ru, --relative-urls     Re-writes relative urls to the base less file.-sm=on|off               Turns on or off strict math, where in strict mode, math.--strict-math=on|off     Requires brackets. This option may default to on and thenbe removed in the future.-su=on|off               Allows mixed units, e.g. 1px+1em or 1px*1px which have units--strict-units=on|off    that cannot be represented.--global-var='VAR=VALUE' Defines a variable that can be referenced by the file.--modify-var='VAR=VALUE' Modifies a variable already declared in the file.--url-args='QUERYSTRING' Adds params into url tokens (e.g. 42, cb=42 or 'a=1&b=2')--plugin=PLUGIN=OPTIONS  Loads a plugin. You can also omit the --plugin= if the plugin beginsless-plugin. E.g. the clean css plugin is called less-plugin-clean-cssonce installed (npm install less-plugin-clean-css), use either with--plugin=less-plugin-clean-css or just --clean-cssspecify options afterwards e.g. --plugin=less-plugin-clean-css="advanced"or --clean-css="advanced"------------------------- Deprecated ------------------line-numbers=TYPE      Outputs filename and line numbers.TYPE can be either 'comments', which will outputthe debug info within comments, 'mediaquery'that will output the information within a fakemedia query which is compatible with the SASSformat, and 'all' which will do both.--verbose                Be verbose.-x, --compress           Compresses output by removing some whitespaces.We recommend you use a dedicated minifer like less-plugin-clean-css