Transmission is a great BitTorrent client. It is full of features (look at the site!), including bandwidth control, and runs on every platform (Linux and Mac :P).
You can choose global upload and download speeds, or shape single torrents among those you are working with.
At home I have a 10mbit connection to the Internet so I rarely limit the torrents, but most of the time when I do it is to reserve a small quantity of bandwidth for Internet browsing while I wait, or to play online.

Transmission is a bit rigid regarding the possible speeds: the only possible values (for both upload and download) expressed in kilobytes/sec are 5, 10, 20, 30, 40, 50, 75, 100, 150, 200, 250, 500, 750, 1000, 1500, 2000. My home network chokes around 600. I could set for 500k, but where’s the fun?

So:

• head to https://trac.transmissionbt.com/wiki/Building and read thoroughly [the part specifying that you need to have XCode installed, for example]
• learn that “Building the project on Mac requires the source to be retrieved from SVN. Pre-packaged source code will not compile.“
• download the SVN code (uhm, yes. I also have pkgsrc installed):
  svn co svn://svn.transmissionbt.com/Transmission/trunk Transmission
  in my case the version number was 2.11 1133-something.
• run a “dry” compile run — this will guarantee that the code is not broken before you start tinkering with it or that you have some local issue (my first time doing actually something with XCode. Easier than I thought, the source has an XCode project file)
• find the relevant source files (grep was my friend). In the end I only modified Controller.m and TorrentTableView.m: find the line
  const NSInteger speedLimitActionValue[] = { 5, 10, 20, 30, 40, 50, 75,
100, 150, 200, 250, 500, 750, 1000, 1500, 2000, -1 };
  and modify it to match the speeds you want to be able to use. You can add or remove values as you like as long as the syntax is right.
• compile it again and run it. :)

If I were a programmer, I’d have implemented something that would allow the user to choose the speed as he liked — but this fits my needs.

(it turns out that Husdawg LLC is a perfectly “legal” ActiveX provider, but Intel does not mention them anywhere — just hoping people will click through?)

Well, I learned (thanks Google) that Snow Leopard does a secure erase of the trash by default. Annoying.
And that I did not realize that until now. Embarassing.

So, this can be solved at least in two ways:

The GUI one
Go into Finder preferences, Advanced, and uncheck “Empty Trash securely”

or

the CLI one
Go into ~/Library/Preferences, convert the Finder preferences to xml (it’s binary by default)
plutil -convert xml1 com.apple.finder.plist
and change the stanza

<key>EmptyTrashSecurely</key>
<true/>
to
<key>EmptyTrashSecurely</key>
<false/>

weird.
The very same www.flickr.vip.mud.yahoo.com handles api.flickr.com (which is, unsurprisingly, down).
Doesn’t look smart from here.

I grew tired of asking myself what OSX was deleting (the operation can take a while, especially when — as I often do — you’re doing a secure erase) so this ugly one-liner, run as root, will give you the file the OS is working on:


ps auxw | grep -i locum | grep -v grep | awk '{print $2}' | xargs lsof -p | grep -i Trash | awk '{print $9}'


It will output something like this:
/Volumes/FAT80GB/.Trashes/502/xcode3210a432.dmg

You can wrap that command inside the usual while/sleep loop if you want something that keeps you updated on what is going on — or make it an alias for your favourite shell.

Now, no doubt it is handy and user-friendly and automagical and… but I feel it disturbing: if by chance I hand over the laptop to somebody for a quick glance at a web page, for example, she can use it to connect anywhere without my consent — ok, I’m oversimplifying, but you get the idea.

The mistery lies into our old friend ssh-agent: it is spawn using
/System/Library/LaunchAgents/org.openbsd.ssh-agent.plist
[on a single line for yout copying pleasure] as a configuration file and it will cache your passphrase the first time you use ssh.
Up to here it’s fine.

What is troublesome to me is that the default cache time is unlimited (see the man page, this is the default behaviour when it is launched without specifying a “-t” option) therefore it will never forget the passphrase until I logout — being the only user of my laptop, this does not happen often.

Enter the joy of xml configuration files: edit the org.openbsd.ssh-agent.plist, and add the option to your liking, that is change this

<array>
<string>/usr/bin/ssh-agent</string>
<string>-l</string>
</array>

to something like this

<array>
<string>/usr/bin/ssh-agent</string>
<string>-l</string>
<string>-t</string>
<string>120</string>
</array>

if a couple of minutes of “grace period” suit your usage.
Then, just kill the process — it will spawn again the next time you use ssh.

[By the way:
Dear Internet, posting code like the XML up here sucks big time.
It took me more time to format the two snippets to render correctly then writing the whole post.
What do you use to ease this pain?
thank you.]

Avevo sempre avuto la curiosita` di provare nginx, ma l’ultima volta che ci avevo guardato era ricco di documentazione, in una sola lingua, e non quella che speravo: il russo. :-)

Invece dopo aver dato un’occhiata al wiki di documentazione, oggi ci ho provato.
E` stata una migrazione pressoche` indolore, a parte un fastidioso problema (mio) all’interno di una stanza di configurazione (sua). Una volta capito il perche` alcune cose non funzionavano come mi aspettavo (dopo che mettere l’access.log a livello di debug, aver ricompilato l’eseguibile con --with-debug, e — alla soglia della disperazione — essermi attaccato con ktrace all’eseguibile).

Rispetto a “lighty” la complessita` del file di configurazione e` forse di poco minore, come l’occupazione di memoria. Le performance sono per entrambi indiscutibili, nei prossimi mesi vedremo se quello che mi ha spinto a provare altro rispetto a lighty funziona meglio.
Da sottolineare che rispetto a lighty (singolo processo, singolo thread e I/O non bloccante con poll/epoll/kqueue/…), nginx e` piu` “alla Apache”, con un processo master e un numero configurabile di figli.
Apprezzabile, dal mio punto di vista, che nginx di default tenda ad installarsi in una directory di /usr/local dentro cui mette tutto (log, configurazione, file html): dal mio punto di vista questo permette di mantenere piu` pulito il filesystem.
Se siete interessati, qui c’e` un documento che spiega come configurarlo con particolare attenzione alla sicurezza.

Una curiosita`: lighttpd e` un progetto figlio di Dan Kegel, autore dell’interessante documento (nonostante sia del 2006) “The C10K problem” — problema che anche nginx afferma esplicitamente di risolvere. :-)