[insert gag reflex onomatopoeia here]
ssh tunnel to circumvent a firewall
My work place like many others has a pretty restrictive firewall that doesn’t let me ssh into my own machine. To get in the network, one has to use VPN which means that a furious battle will rage getting this to work in linux; but above all you won’t get to ssh from your phone.
So if you have a home server, run the following command on your work machine and it will create a tunnel from your work machine to your home server:
ssh -f -N -R 1337:localhost:22 root@home_server
Now login to your home server and when you
ssh localhost -p 1337
You will in fact be sshing to your work machine via magic fairies & such.
It adds a level of indirection which sucks major balls, so you can copy some keys and get all that automated but I don’t want to go into these details. Figure it out.
You can go away now.
Count how many file descriptors are being used by every process of a certain name
here’s a neat little command:
ps -ae | grep <process_name> | perl -lane ‘print $F[0]’ | while read filename; do ls /proc/$filename/fd; done | wc -w
just replace process_name by httpd for example and it’ll tell you how many file descriptions are in use by all the processes with http in them.