npm install -g less does not work: EACCES: permission denied

Mac OS X Answer

You don't have write access to the node_modules directory

npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules

Add your User to the directory with write access

1. Open folder containing node_modules

   open /usr/local/lib/

2. Do a cmd+I on the node_modules folder to open the permission dialog
3. Add your user to have read and write access in the sharing and permissions section

Using sudo is not recommended. It may give you permission issue later. While the above works, I am not a fan of changing folders owned by root to be writable for users, although it may only be an issue with multiple users. To work around that, you could use a group, with 'npm users' but that is also more administrative overhead. See here for the options to deal with permissions from the documentation: https://docs.npmjs.com/getting-started/fixing-npm-permissions

I would go for option 2:

To minimize the chance of permissions errors, you can configure npm to use a different directory. In this example, it will be a hidden directory on your home folder.

Make a directory for global installations:

 mkdir ~/.npm-global

Configure npm to use the new directory path:

 npm config set prefix '~/.npm-global'

Open or create a ~/.profile file and add this line:

 export PATH=~/.npm-global/bin:$PATH

Back on the command line, update your system variables:

 source ~/.profile

Test: Download a package globally without using sudo.

npm install -g jshint

If still show permission error run (mac os):

sudo chown -R $USER ~/.npm-global   

This works with the default ubuntu install of:

sudo apt-get install nodejs npm

I recommend nvm if you want more flexibility in managing versions: https://github.com/creationix/nvm

On MacOS use brew, it should work without sudo out of the box if you're on a recent npm version. Enjoy :)

Run these commands in a terminal window (note: DON'T replace the $USER part... thats a linux command to get your user!):

sudo chown -R $USER ~/.npm
sudo chown -R $USER /usr/lib/node_modules
sudo chown -R $USER /usr/local/lib/node_modules