Modify /etc/environment with ease! Append, prepend to your PATH, define and undefine variables! Last version is always in /etc/environment.bckp.

env-edit.rb

#!/opt/rubies/ruby-2.1.2/bin/ruby -i.bckp

# Usage:
# ./env-edit.rb [var] delete [optional file]
# ./env-edit.rb [var] [append|prepend|replace|remove] [value] [optional file]
# ./env-edit.rb PATH append /opt/rubies/rbx-2.2.6/bin/rbx

OPERATIONS = ['add', 'delete', 'append', 'prepend', 'replace', 'remove']

variable, operation = ARGV.shift(2)

unless OPERATIONS.include?(operation)
  abort "Operation #{operation} is not permitted. Options are: #{OPERATIONS.inspect}"
end

if (OPERATIONS - ['delete']).include?(operation)
  value = ARGV.shift
end

# ARGF assumes all arguments have been deleted from ARGV.
ARGV.push('/etc/environment') if ARGV.empty?

def modify(serialised_array, value, method)
  dirs = serialised_array.split(':')
  dirs.send(method, value)
  dirs.uniq.join(':')
end

ARGF.each_line do |line|
  if match = line.match(/#{variable}="(.+)"/)
    new_value = case operation
    when 'append'  then modify(match[1], value, :push)
    when 'prepend' then modify(match[1], value, :unshift)
    when 'remove'     then modify(match[1], value, :delete)
    when 'replace' then value
    when 'delete' # return nil
    end

    puts line.sub(match[1], new_value) unless line.nil? || line.empty?
  else
    puts line
  end
end

# TODO: This should check where it has already been defined.
if operation == 'add'
  puts "#{variable}=#{value}"
end

cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"

sudo ./env-edit.rb PATH append /opt/node-0.10.28/bin

cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/opt/node-0.10.28/bin"

Hi, can you please clarify the distribution license?