# filenamify > Convert a string to a valid safe filename On Unix-like systems, `/` is reserved. On Windows, [`<>:"/\|?*`](http://msdn.microsoft.com/en-us/library/aa365247%28VS.85%29#naming_conventions) along with trailing periods are reserved. ## Install ``` $ npm install filenamify ``` ## Usage ```js const filenamify = require('filenamify'); filenamify(''); //=> 'foo!bar' filenamify('foo:"bar"', {replacement: '🐴'}); //=> 'foo🐴bar' ``` ## API ### filenamify(string, options?) Convert a string to a valid filename. ### filenamify.path(path, options?) Convert the filename in a path a valid filename and return the augmented path. #### options Type: `object` ##### replacement Type: `string`\ Default: `'!'` String to use as replacement for reserved filename characters. Cannot contain: `<` `>` `:` `"` `/` `\` `|` `?` `*` ##### maxLength Type: `number`\ Default: `100` Truncate the filename to the given length. Systems generally allow up to 255 characters, but we default to 100 for usability reasons. ## Browser-only import You can also import `filenamify/browser`, which only imports `filenamify` and not `filenamify.path`, which relies on `path` being available or polyfilled. Importing `filenamify` this way is therefore useful when it is shipped using `webpack` or similar tools, and if `filenamify.path` is not needed. ```js const filenamify = require('filenamify/browser'); filenamify(''); //=> 'foo!bar' ``` ## Related - [filenamify-cli](https://github.com/sindresorhus/filenamify-cli) - CLI for this module - [filenamify-url](https://github.com/sindresorhus/filenamify-url) - Convert a URL to a valid filename - [valid-filename](https://github.com/sindresorhus/valid-filename) - Check if a string is a valid filename - [unused-filename](https://github.com/sindresorhus/unused-filename) - Get a unused filename by appending a number if it exists - [slugify](https://github.com/sindresorhus/slugify) - Slugify a string