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Detects dead CSS.

Build Status

A demonstration of Mort


You can use the binaries on the releases page for versions 1.5 and above.

Or if you like, use npm.

npm i mort-css

Or globally with

npm i -g mort-css

You should then be able to run mort.


cd to the root of the project you're interested in and run mort to scan that css file against your codebase.

Normal use

mort -f your-css-file.css

Verbose output

mort -f your-css-file.css -v

Forcing use of git grep

mort -f your-css-file.css -p gitgrep


If no arguments are supplied, mort reads from stdin.


cat my-css-file.css | mort


echo "#my-selector-to-hunt-for" | mort

Multiple CSS files

It's possible to scan multiple CSS files with mort.

ls assets/css/*.css | xargs -L1 mort -v -f 

Ignoring some files with find

find -iname *.scss -not -path "./node_modules/*" | xargs -L1 mort -vf


  Usage: mort [options]


    -V, --version               output the version number
    -u, --usage-count <number>  Show warnings for any css selector <= usage-count. (default: 0)
    -v, --verbose               Detailed information about the matches will be displayed.
    -f, --file <path>           The css file to run mort against.
    -p, --program <program>     Force mort to use a grep program of your choice. Supported ones are 'ripgrep', 'gitgrep', and 'grep'.
    -h, --help                  output usage information

-u --usage-count

This will show all selectors that are <= to the specified count.


mort -f your-css-file.css -u 3

Will display all selectors that are used 3 times or less. This is particularly useful to find selectors that can be combined into classes etc...

-v --verbose

This toggles verbosity. There are currently 3 levels of verbosity.

Level 1

mort -f somefile.css -v

Level 1 displays what file it is scanning and the line count for that selector.

Level 2

mort -f somefile.css -vv

Level 2 displays level 1 + The command used to find the selector

Level 3

mort -f somefile.css -vvv

Level 3 displays level 1 + level 2 and shows all selectors it is searching through (regardless of whether they are used or not).

-f --file

The file to run mort against. If unspecified, mort will read from stdin.

-p --program

Which grep program to use. The default is ripgrep as it's the quickest. Supported grep programs are ripgrep, gitgrep, and grep.

Note that grep is incredibly slow so is not recommended

Using the default (ripgrep)

mort -f somefile.css

Using git grep

mort -f somefile.css -p gitgrep

Using grep

mort -f somefile.css -p grep


  • One of either:
    • ripgrep
    • git grep
    • grep (Not recommended, very slow with mort)

Note that this tool can't detect all use cases. For example, string-concatting a selector in JS will probably bypass the tool.