Q: Why program is killed if I log out the bash and why it survive if using nohup?

A: When log out, the bash will generate the SIGHUP to progress attached to it. If there is no default routine in progress to handle this signal, kernel will use the default action (terminate for SIGHUP). More information see section 10.2 of “Advanced Programming in the UNIX Environment” or http://www.win.tue.nl/~aeb/linux/lk/lk-10.html .

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Recently I just realize how good the RSS did. By using RSS, you have kind of information center to read all interesting information from different site and it is a good idea. It is similar with email but only with one direction.

But seems RSS is not popular any more, we talk with twitter, facebook, G+ and many others. But why not RSS.

This is a interesting thing and worth to think.

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I am thinking about the difference between email, QQ/MSN, twitter,blog, Facebook/Google+, Yelp/Dianping, Douban, Google group, web forum and mail group. It is possible to merge them together? Actually it is all about how to distribute information.

The first step is to identify who you are. In email, we use email address; in QQ/MSN, we use QQ number/Windows live ID; in web forum, we use user name. One thing need to emphasize, email is wonderful. Since we could talk with other in different world. But for others, you could only talk with one in same world. I think we need to talk with other worlds since it is impossible and not safe to only have one identify system. But in QQ/MSN world, it seems we lost it. But web forum/web site, open ID is a good solution, but seems still long way to work.

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