rsync in linux

1) rsync in linux
1@@@@ local
@@@
@@@<1> use rsync, remote or local synchron target file. case1
@@@
    Case1: source and target have the same filename, but content are differents.
           Then you run the rsync, What is the result?
   
    [root@station78 ~]# ls -R source_file/ target_file/
    source_file/:
    file1  file2
   
    target_file/:
    file1  file2
   
   @@@source dir:
    [root@station78 ~]# cd source_file/
    [root@station78 source_file]# cat file1
    111
    222
    333
    [root@station78 source_file]# cat file2
    111
    222
    333
   
   @@@target dir:
    [root@station78 ~]# cd target_file/
    [root@station78 target_file]# cat file1
    111
    222
    [root@station78 target_file]# cat file2
    111111111111111111111111111111111
   
   @@@
   @@@Testing contents
    [root@station78 ~]# rsync -avz source_file/ target_file/
    sending incremental file list
    ./
    file1
    file2
   
    sent 162 bytes  received 53 bytes  430.00 bytes/sec
    total size is 24  speedup is 0.11
    [root@station78 ~]# cd target_file/
    [root@station78 target_file]# cat file1
    111
    222
    333
    [root@station78 target_file]# cat file2
    111
    222
    333
   
   
   
@@@
@@@<2> local case2
@@@
    Case2: source and target have different filename, then What's the result?
       
   @@@source dir:
    [root@station78 ~]# cd source_file/
    [root@station78 source_file]# cat file1
    111
    222
    333
    [root@station78 source_file]# cat file2
    111
    222
    333
   
   @@@target dir:
    [root@station78 target_file]# pwd
    /root/target_file
    [root@station78 target_file]# ls
    file3
    [root@station78 target_file]# cat file3
    xxxx
   
   @@@Testing
    [root@station78 ~]# rsync -avz source_file/ target_file/
    sending incremental file list
    ./
    file1
    file2
   
    sent 162 bytes  received 53 bytes  430.00 bytes/sec
    total size is 24  speedup is 0.11
   
   @@@
   @@@Result: file3 do not be removed, and add file1 and file2.
    [root@station78 ~]# cd target_file/
    [root@station78 target_file]# ls
    file1  file2  file3
    [root@station78 target_file]# cat file1
    111
    222
    333
    [root@station78 target_file]# cat file2
    111
    222
    333
    [root@station78 target_file]# cat file3
    xxxx
   
   
2@@@@ remote
      the same, just add user@[hostname|ip]:dir
      like
      rsync -avz root@station15:/root/sourcedir  /root/targetdir
      rsync -avz /root/sourcedir            root@station78:/root/targetdir
   
    Bear in mind:
      It is the files in source directory were copy to the target directory,
      if there are the same filename in target dir,
         then cover it by the file in source directory,
      if there are not the same filename in target dir,
         then do nothing.
   
3@@@@ When we need this tool?
    You backup something big.
      such as
      When I backup my Documents to my moving disk, It is very convenient and speed.
   
      You could use this in your shell script, then the shell script could be run in
      crontab for daily backup something. It is magic.