View method: 1. Use "rpm -qa" to check. This command can find whether a certain software package is installed. The syntax is "rpm -qa|grep rsync". If the result has an rsync name, it means it has been installed; 2. Use the "rsync Enter" method to check. If a help message appears, it means that rsync has been installed.
#The operating environment of this tutorial: linux7.3 system, Dell G3 computer.
Check method:
1. You can use rpm -qa to see. If you want to find out whether a certain software package is installed, use rpm -qa | grep "the name of the software or package".
[root@test home]# rpm -qa|grep rsync
When the rsync package name appears, it means it is installed.
2. Press Enter for rsync.
appears. The help information indicates that it has been installed
Extended knowledge:
Rsync service, that is, Remote Sync service, remote synchronization service, is a type of transmission synchronization used in remote or local places Serve. Compared with general cp and scp tools, the advantages of Rsync service are as follows:
1. The backup is an incremental backup, and only modified files are transferred.
2. Before and after file transfer, the transferred files will be compressed, thereby reducing the transmission bandwidth and transmission time.
3. The entire directory tree and file system can be backed up, and soft and hard links, time, file attributes, etc. can be selectively backed up.
The Rsync service adopts C/S mode and uses port number 873. The server of Rsync refers to the device that turns on the Rsync service and listens to port 873. There are two data synchronization methods of Rsync service, push and pull. Push is the push method. The Rsync client actively pushes the data to be backed up to the Rsync server. At this time, the important data is stored in the client, and the client sends the data to the server for storage. pull, that is, the pull method, the Rsync client actively looks for the Rsync server to obtain backup data. At this time, important data is stored in the server, and the client realizes local backup of important data through pulling actions.
When using push, if there are too many devices, the delay will be very high, so it is generally used in scenarios with less than 20 backup devices. In the company's intranet, if there are a large number of servers, you can configure the Rsync service in a multi-level configuration. The scenario is as follows:
Xinetd service will uniformly manage Rsync, tftp, DHCP, etc. Small service. When using Rsync to synchronize, first listen to port 873 through xinetd. If Rysnc information is received, it will be forwarded to the Rysnc service, and then the Rysnc service will respond.
Recommended learning: Linux video tutorial
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