Sunday, October 19, 2008

Screen, nohup, ssh, scp

I learned a lot about the above in the past day, but I didn't keep track of the links.

First, screen is very useful: it allows you to run any task, detach the screen, and let it run in the background. You can resume it later.


<ctrl-a> d
screen -r

Second, it's a huge pain to type a password every time I use scp and ssh. The solution is to make a key on your computer and put it in the authorized_keys file.

ssh-keygen -t rsa
scp ~/.ssh/id_rsa
cat id_rsa >> ~/.ssh/authorized_keys
ssh -v

Use ssh -v to figure out why it fails if it still asks you for a password. In one case, this happened because the computer I was using expected the id to be in ~/.ssh/identity instead of ~/.ssh/id_rsa. There may also be permissions issues (i.e. you want restrictive permissions on your ssh keys).

With the latter, you can still use nohup, which is helpful if you want to pipe your output to a log file.

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