LESSlint is a linter for LESS files.
It is intended to check the code quality and compliance with standards.

PHP 5.4+

lesslint rules.json /path/to/less/folder/ /path/to/file.less
    --exclude=file.less,lib.less
    --recursive

• --exclude takes file names separated by commas;
• --recursive recursively browse through the folders to find LESS files.

• IndentWithTabs: use tabs to indent the code, not spaces;
• OneSpaceBeforeBracket: one space before a bracket: .stuff {;
• WrongIndent: check if each line is properly intended regarding to the code depth;
• ClosingBracketOnItsOwnLine: closing bracket must be on its own line;
• ValidCssProperty : check for non-existing CSS properties (supports CSS3 and vendor prefixes);
• OnePropertyPerLine: max one property per line;
• ColonSpacing: no space before a colon; one after;
• NotImportant: do not use !important;
• OverQualifiedSelector: do not overqualify the selectors. div.stuff → .stuff;
• DoNotStyleIds: do not apply a style to IDs (#), use classes;
• OpeningBracketInline: opening bracket should be inline, not on its own line.

Rules file contains the list of rules to be enforced as keys; their parameter a values or true if the rule does not support extra parameters:

{
	"IndentWithTabs": true,
	"NotImportant": true,
	"OneSpaceBeforeBracket": true,
	"WrongIndent": true,
	"ClosingBracketOnItsOwnLine": true,
	"ValidCssProperty": true,
	"OnePropertyPerLine": true,
	"ColonSpacing": true,
	"OverQualifiedSelector": true,
	"NoUnitToZero": true,
	"OpeningBracketInline": true
}