CLEANCSS(1)

💖 NAME 💖

okay so bestie, meet cleancss — a fast and efficient CSS optimizer. she takes your chunky stylesheet and makes it ✨snatched✨. no cap.

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🦋 SYNOPSIS 🦋

cleancss [options] <source-file ...>

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👑 OPTIONS 👑

• -v, --version — outputs the version number. that's the whole job, and she does it flawlessly 💅
• -c, --compatibility [ie7|ie8] — forces compatibility mode. (there are advanced examples in the Readme if you wanna go deeper, iykyk)
• -d, --debug — shows debug information: the minification time and the compression efficiency. receipts, basically 🧾
• -f, --format <options> — controls the output formatting. examples are down below ⬇️
• -o, --output [output-file] — uses [output-file] as the output instead of STDOUT. she can pick a destination, she's not like other girls.
• -O <n> [optimizations] — turns on level n optimizations. optionally she'll accept a list of fine-grained options too. defaults to 1. examples below 🔥
• --inline [rules] — enables inlining for the listed sources. defaults to local.
• --inline-timeout [seconds] — per-connection timeout when she's out here fetching remote stylesheets. defaults to 5 seconds.
• --remove-inlined-files — removes files that were inlined in <source-file ...> or via @import statements.
• --skip-rebase — disables URLs rebasing.
• --source-map — enables building the input's source map.
• --source-map-inline-sources — enables inlining sources inside source maps.
• --input-source-map [file] — specifies the path of the input source map file.
• -h, --help — outputs usage information. the iconique classic.

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🎀 Examples: 🎀

%> cleancss one.css

%> cleancss -o one-min.css one.css

%> cleancss -o merged-and-minified.css one.css two.css three.css

%> cleancss one.css two.css three.css | gzip -9 -c > merged-minified-and-gzipped.css.gz

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🌈 Formatting options: 🌈

%> cleancss --format beautify one.css

%> cleancss --format keep-breaks one.css

%> cleancss --format 'indentBy:1;indentWith:tab' one.css

%> cleancss --format 'breaks:afterBlockBegins=on;spaces:aroundSelectorRelation=on' one.css

so here's the whole menu of formatting knobs, bestie:

• breaks — controls where to insert breaks.
  • afterAtRule — controls if a line break comes after an at-rule, e.g. @charset. defaults to off (alias to false).
  • afterBlockBegins — controls if a line break comes after a block begins, e.g. @media. defaults to off.
  • afterBlockEnds — controls if a line break comes after a block ends. defaults to off.
  • afterComment — controls if a line break comes after a comment. defaults to off.
  • afterProperty — controls if a line break comes after a property. defaults to off.
  • afterRuleBegins — controls if a line break comes after a rule begins. defaults to off.
  • afterRuleEnds — controls if a line break comes after a rule ends. defaults to off.
  • beforeBlockEnds — controls if a line break comes before a block ends. defaults to off.
  • betweenSelectors — controls if a line break comes between selectors. defaults to off.
• indentBy — controls the number of characters to indent with. defaults to 0.
• indentWith — controls the character to indent with. can be space or tab. defaults to space.
• spaces — controls where to insert spaces.
  • aroundSelectorRelation — controls if spaces come around selector relations, e.g. div > a. defaults to off.
  • beforeBlockBegins — controls if a space comes before a block begins, e.g. .block {. defaults to off.
  • beforeValue — controls if a space comes before a value, e.g. width: 1rem. defaults to off.
• wrapAt — controls the maximum line length. defaults to off.

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⭐ Level 0 optimizations: ⭐

%> cleancss -O0 one.css

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💅 Level 1 optimizations: 💅

%> cleancss -O1 one.css

%> cleancss -O1 removeQuotes:off;roundingPrecision:4;specialComments:1 one.css

%> cleancss -O1 all:off;specialComments:1 one.css

and the fine-grained level 1 girlies:

• cleanupCharsets — controls @charset moving to the front of a stylesheet. defaults to on.
• normalizeUrls — controls URL normalization. defaults to on.
• optimizeBackground — controls background property optimizations. defaults to on.
• optimizeBorderRadius — controls border-radius property optimizations. defaults to on.
• optimizeFilter — controls filter property optimizations. defaults to on.
• optimizeFontWeight — controls font-weight property optimizations. defaults to on.
• optimizeOutline — controls outline property optimizations. defaults to on.
• removeEmpty — controls removing empty rules and nested blocks. defaults to on (since 4.1.0).
• removeNegativePaddings — controls removing negative paddings. defaults to on.
• removeQuotes — controls removing quotes when they're unnecessary. defaults to on.
• removeWhitespace — controls removing unused whitespace. defaults to on.
• replaceMultipleZeros — controls removing redundant zeros. defaults to on.
• replaceTimeUnits — controls replacing time units with shorter values. defaults to on.
• replaceZeroUnits — controls replacing zero values with units. defaults to on.
• roundingPrecision — rounds pixel values to N decimal places; off disables rounding. defaults to off.
• selectorsSortingMethod — denotes the selector sorting method; can be natural or standard. defaults to standard.
• specialComments — denotes a number of /*! ... */ comments preserved. defaults to all.
• tidyAtRules — controls at-rules (e.g. @charset, @import) optimizing. defaults to on.
• tidyBlockScopes — controls block scopes (e.g. @media) optimizing. defaults to on.
• tidySelectors — controls selectors optimizing. defaults to on.

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🔥 Level 2 optimizations: 🔥

%> cleancss -O2 one.css

%> cleancss -O2 mergeMedia:off;restructureRules:off;mergeSemantically:on;mergeIntoShorthands:off one.css

%> cleancss -O2 all:off;removeDuplicateRules:on one.css

and the level 2 menu, all of it, no skips:

• mergeAdjacentRules — controls adjacent rules merging. defaults to on.
• mergeIntoShorthands — controls merging properties into shorthands. defaults to on.
• mergeMedia — controls @media merging. defaults to on.
• mergeNonAdjacentRules — controls non-adjacent rule merging. defaults to on.
• mergeSemantically — controls semantic merging. defaults to off.
• overrideProperties — controls property overriding based on understandability. defaults to on.
• reduceNonAdjacentRules — controls non-adjacent rule reducing. defaults to on.
• removeDuplicateFontRules — controls duplicate @font-face removing. defaults to on.
• removeDuplicateMediaBlocks — controls duplicate @media removing. defaults to on.
• removeDuplicateRules — controls duplicate rules removing. defaults to on.
• removeEmpty — controls removing empty rules and nested blocks. defaults to on (since 4.1.0).
• removeUnusedAtRules — controls unused at rule removing. defaults to off (since 4.1.0).
• restructureRules — controls rule restructuring. defaults to off.
• skipProperties — controls which properties won't be optimized. defaults to an empty list, which means all of them will be optimized (since 4.1.0).

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💜 this page is from cleancss 4.3.0, dated February 2020, and it lives in section 1 of the manual (User Commands). go forth and minify, bestie 🫶✨