Compiling

To compile LibTorrent I needed to install the libsigc++-2.0-dev package. To compile RTorrent I needed to install libcurl4-openssl-dev. Both can be installed via apt-get:

sudo apt-get install libsigc++-2.0-dev libcurl4-openssl-dev

Updating .rtorrent.rc

The New Ratio Syntax

This actually has been documented to some extent on the RTorrentRatioHandling wiki page. Unfortunately “The basics” make little sense to me. Here is what I did:

Remove my old schedule command to stop torrents when they reach a certain ratio:

schedule = ratio,60,60,"stop_on_ratio=100"

And replace it with:

# Enable the default ratio group.
ratio.enable=
 
# Change the limits
ratio.min.set=100
#ratio.max.set=300
#ratio.upload.set=20M

My desired behavior is for RTorrent to close a torrent when its ratio reaches 1.0 which is why I am only setting ratio.min.set.

I am extremely curious why the developer decided to make the configuration command to enable ratios ratio.enable=. The equals sign on the end of the line makes the option feel very incomplete and does not make sense.

Deprecated on_* commands

All of the on_* commands are now deprecated.¹ This includes on_start, on_stop, on_finished, and on_erase. I use an on_finished command to move finished torrents to a separate directory which had to be changed.

# deprecated on_finished command
# on_finished = move_complete,"d.set_directory=~/torrents/finished/ ;execute=mv,-u,$d.get_base_path=,~/torrents/finished/"
 
# Equivalent on_finished for rtorrent > 0.8.4
system.method.set_key = event.download.finished,move_complete,"d.set_directory=~/torrents/finished/ ;execute=mv,-u,$d.get_base_path=,~/torrents/finished/"

DTach

On a whim I decided to switch to running RTorrent with dtach instead of inside GNU Screen. My hope is that dtach will perform a little better. Unfortunately when I opened RTorrent with dtach my arrow keys changed my download threshold instead of navigating the list of torrents. A fix that I found is to specify TERM=linux when launching dtach.²

env TERM=linux dtach -c /tmp/rtorrent.dtach rtorrent

Once again I find it why this works to be a mystery but no explanation was given.

Rant

I have a lot of respect for the creator of RTorrent/LibTorrent. He has created an excellent Bittorrent client and backend that I have been happily been using for a couple years. However, I think it is very poor form that he released new updates that change the configuration interface without properly documenting the upgrade path on the website. This was frustrating enough that I tried to update the LibTorrent trac but public accounts are not allowed, blocking my attempt to help.

Here are my straightforward, no nonsense instructions for setting up password-less ssh remote login.

Note: In these instructions I refer to a local computer and a remote computer. The local computer is your personal computer or the computer your are running ssh from and the remote computer is the computer you are connecting to. If you are connecting to a server that is the remote computer.

Begin by running ssh-keygen -t dsa on your local computer. The output will look something like this. When it asks for a passphrase enter something but remember what it is as you will have to enter it again. Later we will find out how to save the passphrase using keychain so we do not have to enter it every time.

$ ssh-keygen -t dsa
Generating public/private dsa key pair.
Enter file in which to save the key (/Users/rob/.ssh/id_dsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /Users/rob/.ssh/id_dsa.
Your public key has been saved in /Users/rob/.ssh/id_dsa.pub.
The key fingerprint is:
e1:9c:c3:55:9a:ab:5f:7d:db:0c:bf:02:67:cd:ac:ce rob@athena.local

This will create two files, ~/.ssh/id_dsa and ~/.ssh/id_dsa.pub. Next we need to append id_dsa.pub to ~/.ssh/authorized_keys2 on the remote computer

cat .ssh/id_dsa.pub | ssh remote_computer_ip "cat >> .ssh/authorized_keys2"

Insert the IP address of the remote computer and run the command (it is all one line). Once that is done the ssh keys are now setup. Test it by connecting to the remote computer.

% ssh username@remote-computer
Enter passphrase for key '/home/rob/.ssh/id_dsa':

After entering the correct passphrase the remote computer will finish the login process.

At this point we are no better off then we were before. Entering a phasephrase is often more work than a password. To save us the work of entering our passphrase each time we can use Keychain programs. There are keychain programs for OS X and Linux.

Keychain on Mac OS X: OS X 10.5 will store ssh passphrases in the OS X Keychain the first time you attempt to login.

Keychain on Linux: On linux we need to install a program similarly named ‘keychain’. Seek out and install keychain from your distribution’s repositories. After it is installed we need to add the following lines to ~/.bash_profile.

keychain id_dsa
source ~/.keychain/$HOSTNAME-sh

Now test it by reopening terminal and keychain should run. Once your passphrase is stored in keychain you will be able to login to the remote computer without being prompted for a passphrase.

Note about RSA: You may have seen RSA keys used instead of DSA keys. RSA encryption is used by version 1 of the ssh protocol whereas DSA is used by version 2. OpenSSH is capable of using both DSA and RSA keys so you may use whichever you like.