0.) Install libev
  # wget http://dist.schmorp.de/libev/libev-3.53.tar.gz
  # tar -zxf libev-3.53.tar.gz
  # cd libev-3.53
  # ./configure && make && make install

1.) Compile

  # cd vusaged
  # ./configure
  # make

2.) Copy to vpopmail location

  # cp -f vusaged /home/vpopmail/bin
  # cp -f etc/vusaged.conf /home/vpopmail/etc

3.) Edit vusaged.conf and vusagec.conf

  # vi /home/vpopmail/etc/vusaged.conf
  # vi /home/vpopmail/etc/vusagec.conf

4.) Create startup (CentOS example)

  # cp contrib/rc.vusaged /etc/init.d/vusaged

  Edit paths
  # vi /etc/init.d/vusaged

  # /sbin/chkconfig --add vusaged
  # /sbin/chkconfig vusaged on

5.) Start it up (CentOS example)

  # /sbin/service vusaged start

6.) Test

  # /home/vpopmail/bin/vusagec user@domain
