daemon
daemon have Chinese names on a very large, called daemons.
There is a saying, if there is no daemon on Unix, Unix then it will not be the same.
It is very personal, is a process running in the background and is not a control terminal, which mostly start with the system and start, no special circumstances will remain closed until the system is running.
It's there for our users and the system itself to provide a useful service. Common are httpd, mysqld, syslogd, are generally daemon name will end with d.
zombie
Linux is in the middle of it when a process is killed, in fact, it will not immediately disappear, but became a zombie, namely zombie process, and then wait for the completion of its parent process to gather information will be cleared.
In general this information gathering process will be completed soon, but sometimes it's busy parent, the zombies will always stay in our system.
From time to time during system operation will have some zombie process, we can not kill them directly, because they are dead, we can only resort to other means, such as to kill its parent process, and then to recover the corpse by the init process .
Emergence of zombie process that produced it is usually expressed in addition to the problem, and it will consume resources, to prevent its appearance.
crypt
crypt, basement, this command is also easy to understand.
When you want to protect your stuff is not known by others, into the basement locked up it is a very good way.
Meaning crypt in Linux is encrypted, now called mcrypt, when you want to encrypt files without being read others, this command will be very convenient. As with most Linux commands, you can use the crypt alone, the system can also be used in the script.
shred
shred, shred. I think you've seen here in these strange words flattering.
It is a very hard guy, is to shred files. When we want to delete a file, we will use the rm command, but this is a means for recovery, then we do not want people to restore how to do? Yes, sherd role in this regard. shred many times before covering the space occupied by the file. So, use this command that should be psychologically prepared, because gods can not put out.
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