SSH is definitely one of my most often used tools, not only for system
administration at work but also on the road with my netbook, an
EeePC
701 running
Debian Sid.
On the road, it often happens that I have a flaky
WLAN or
UMTS
connection, so I often have to kill (via
<Enter>~.)
and reconnect my
SSH session due to a changed
IP address or so.
First step against problems arising from using
SSH over unreliable
network connections is of course
GNU Screen. Second step is use
SSH
keys and ssh-agent to not needing to type the password on every
reconnect.
But it s still very annoying to kill the
SSH connection and call ssh
again manually. For luck there is
autossh, a wrapper around
SSH which
regularily checks via two tunnels connect to each other on the remote
side if the connection is still alive, and if not, it kills the ssh
and starts a new one with the same parameters (i.e. tunnels, port
forwardings, commands to call, etc.).
It s quite obvious that this is perfect to be combined with screen s
-R and
-d options (Reattach if a detached
screen is around, else start a new screen; detach a currently attached
screen), so I found myself very often typing (or fetching it from the
commandline history :-):
autossh -t sym.noone.org 'screen -Rd'
-t is necessary to allocate a terminal device on the
remote machine which is not done by default if you directly call a
command via
ssh.
In comparision to
OpenSSH, autossh needs the single quotes, because
otherwise it would parse
-Rd as options to parse to
ssh and bail out. That s not a real problem, but when
you re used to just type
ssh -t sym.noone.org screen -Rd
without any quotes, you ll run into this then and when.
Update, 25-May-2010, 14:55: As Carsten Hey points
out,
autossh also supports the
-- option to
declare that all following options and parameters must be passed to
ssh itself. (End of Update)
Typing that often and mistyping it then and when cries for an shell
alias or an shell function. So I came up with the following shell
function:
asc()
autossh -x -a -t "$@" 'screen -RdU'
I used a function instead of an alias in case of
autossh
will in future regard all parameters given after the command as part
of the command as
ssh does.
The additional options
-x and
-a disable X
and
SSH Agent forwarding which both don t work if you reattach to an
already running
screen.
And if you re using
Zsh as I do, you can even add some more format
string magic to set the window title more or less to the expanded
alias, eh, function:
function asc()
# Set the title to something more obvious, e.g. the expanded
# alias, eh, function
print -Pn "\e]0;%n@%m: autossh -t $* 'screen -RdU'\a";
autossh -x -a -t "$@" 'screen -RdU'
compdef asc=ssh
Update, 25-May-2010, 14:59: As Hauke points out in a
comment, Zsh users should also declare that
asc should
have the same tab completion as
ssh itself. The example
above has been updated accordingly. (End of Update)
In the meanwhile on the EeePC I use
asc on the
commandline more often than
ssh itself. And I nearly no
more type
autossh. (The most common exception here is
autossh hostname tail -F /path/to/some/logfile.)
Using that function you can also add common
ssh options
for tunneling, etc. I use it most often like this:
asc -D 1080 sym.noone.org
This opens a
SOCKS proxy on localhost, port 1080 and that way I can
surf via the host I m connecting to by
SSH.
There s one small drawback though: You didn t expect that I can just
invent some new three letter command without a namespace clash, did
you? There is a free game called
Advanced Strategic Command whose binary (and
Debian package)
is named
asc, too. If you have that game installed, you
can always call it using its full path, e.g.
/usr/games/asc on Debian.
P.S.: My whole
grml based
.zshrc is also
available via git
at
git.noone.org as well as
on github.
What happened in my running life since my
last update?
In short, I achieved two races I was planning to do.
I ran my first trail on May 16th, Le Trail des Cerfs ("deer trail").
The experience of trail running is awesome. Runners are very friendly
and all of them are nature lovers. So, the feeling is completely
different from mass macadam races (those are also a must-do, still!).
I had a great time running that trail (which ended up to be exactly the
distance of an half marathon). I completed it in
less than 1h50, which is good, as the positive slope was about 300
meters, with sometimes very though rampswhere walking was nearly
mandatory.
At this occasion, during the "after", I discovered some members of an
online community of runners, named Kikourou ("Who is running where?"),
and I'm now a member of this online community (yet another
one...). That makes the promise of lots of beers after races...:-)
Today, I
completed my "Maureparathon", a full marathon ran alone on small
roads and bicycle lanes in my home city, and was
happy to break my personal best by 6 minutes, down to
3h43'14". Yay. For sure, still very far from SuperNo l (3:03:56 in
Mainz), but he's younger..:)
As I planned, I'll be running the
Sur les Traces du Loup
("The Wolf Track"?) 33km trail in La Ville aux Clercs, 2 hours away from our place. Elizabeth
is very happy to come with me in a 2-day trip in Chateaudun
neighbourhood. Renaissance castle visit mandatory for the following Sunday...:-)
Nice planning, eh?
And, guess what? I'm already trying to spot some local 10km races
while being in New York. I would find it an interesting experience to
run with local runners. Just like free software...and beer...and
cheese, running is much better when shared.
The last weeks, I've occasionally been contributing to Wikipedia. I must say,
Wikipedia is a really odd world of its own. Another thing I found quite
surprising is the difference between the English and the German Wikipedia.Some things I noticed:
Yesterday finally my 
I recently noticed the new 
Update: I'm 
People who use and promote free software cite various reasons for their choice, but do those reasons tell the whole story? If, as a community, we want free software to continue to grow in popularity, especially in the mainstream, we should understand better the true reasons for choosing it especially our own.
Some believe that it offers higher quality, that the availability of source code results in a 
I was about to close down a good day of hard work, a heavy but useful day... I had even decided to take some time off to listen to some good music, and was heading off to bed on a good mood...
Until I decided to read my contacts' latest rants. And I found very sad news - again.
I just replaced my aging 2004-era PC with wait for it a 2005-era PC.
A friend is moving across the country so I'm taking it off his hands.
The differences between the two are more than just the year of time,
though: one was hand-built from parts, while the other was a commodity
off-the-shelf Compaq. So the new machine, while not strictly faster by
the clock, is 64-bit and is much more amenable to upgrades.
While the added bulk is a bit annoying, the case has a lot more space in
it up to 8 or so drive slots (I can't imagine ever needing that
many), and 4 RAM slots which is a sure step up from the limitation of
two drive slots and two RAM slots in my old machine.
The most visibly shiny parts in the new desktop experience are 4G RAM
versus 1G, and a nice ATI GPU. While I'm glad my
In response to a