ruby/rubygems · error · Gem::FilePermissionError

You don't have write permissions for the #{directory} direct

Error message

You don't have write permissions for the #{directory} directory.

What it means

Error "You don't have write permissions for the #{directory} directory." thrown in ruby/rubygems.

Source

Thrown at lib/rubygems/installer.rb:313

    end

    write_spec
    write_cache_file

    File.chmod(dir_mode, gem_dir) if dir_mode

    say clean_text(spec.post_install_message.to_s) if options[:post_install_message] && !spec.post_install_message.nil?

    Gem::Specification.add_spec(spec) unless @install_dir

    load_plugin unless options[:install_plugin] == false

    run_post_install_hooks

    spec
  rescue Errno::EACCES => e
    # Permission denied - /path/to/foo
    raise Gem::FilePermissionError, e.message.split(" - ").last
  end

  def run_pre_install_hooks # :nodoc:
    Gem.pre_install_hooks.each do |hook|
      next unless hook.call(self) == false
      location = " at #{$1}" if hook.inspect =~ /[ @](.*:\d+)/

      message = "pre-install hook#{location} failed for #{spec.full_name}"
      raise Gem::InstallError, message
    end
  end

  def run_post_build_hooks # :nodoc:
    Gem.post_build_hooks.each do |hook|
      next unless hook.call(self) == false
      FileUtils.rm_rf gem_dir

      location = " at #{$1}" if hook.inspect =~ /[ @](.*:\d+)/

View on GitHub (pinned to 86cbb817a3)

Solutions

1. Install into your user directory: `gem install --user-install <gem>`
2. Fix ownership/permissions of the gem directory, or use sudo for system installs

When it happens

Trigger: Thrown at lib/rubygems/installer.rb:313 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of ruby/rubygems@86cbb817a3 (2026-08-23). Data as JSON: /api/errors/fc1db3fe55c6ac0c. Report an issue: GitHub.