The SHELL and list are used to handle the transaction.

SHELL and list are used to process the complete events: command-1 & amp; command-2 & amp; command-3 & amp; command-4 & amp; command-n each command returns true and will be executed in sequence. when a command returns false, the command chain will be disconnected and the last one will be false, the last SHELL and list will be used to process the complete transaction command-1 & command-2 & command-3 & command-4 &&... command-n each command returns true and will be executed in sequence. when a command returns false, the command chain breaks down and the last one is false, this is the last command to be executed. today, due to the blind spot of this knowledge, it is a shame that the company testing machine is on the rack of the data center. I went up remotely through ssh, changed the network configuration to static retrieval, and then tried to restart eth0 to make it take effect: ifdown eth0, and the result was suspended. sorry, ssh cannot be logged on. Fortunately, it was a test machine. I ran to the data center and moved one. Monitor, local login, execute: ifup eth0 and list processing: ifdown eth0 & ifup eth0 disconnect the network, it is just a stupid thing to lock yourself out, really do less in the future! The general process is as follows: O & M that will not be developed is not a good DBA !!