Rsync备份一个源目录，并再次检查多个目录

Question

我想将“sdir”目录根据当天的情况复制（rsync）到tdir目录。我想要一个完整的副本到mon目录，只改变了什么，只改变了什么，等等，但我没有得到我需要的结果。 参考实际的命令我跑：

[jesse@localhost test]$ tree 
. 
├── sdir 
│ ├── file1 
│ ├── file2 
│ ├── file3 
│ ├── file4 
│ └── file5 
└── tdir 
    ├── fri 
    ├── mon 
    │ ├── file1 
    │ └── file2 
    ├── thu 
    ├── tue 
    │ └── file3 
    └── wed 
     ├── file3 
     ├── file4 
     └── file5 

7 directories, 11 files 
[jesse@localhost test]$ touch sdir/file6 
[jesse@localhost test]$ rsync -av --dry-run sdir/ --compare-dest=/home/jesse/test/tdir/mon/ /home/jesse/test/tdir/tue/ /home/jesse/test/tdir/wed/ /home/jesse/test/tdir//thu/ --backup-dir=/home/jesse/test/tdir/fri/ 
sending incremental file list 
./ 
file3 
file4 
file5 
file6 

sent 294 bytes received 31 bytes 650.00 bytes/sec 
total size is 0 speedup is 0.00 (DRY RUN) 
[jesse@localhost test]$ rsync -av --dry-run sdir/ --compare-dest=/home/jesse/test/tdir/mon/ /home/jesse/test/tdir/tue/ /home/jesse/test/tdir/wed/ /home/jesse/test/tdir//thu/ --backup-dir=/home/jesse/test/tdir/thu/ 
sending incremental file list 
./ 
file3 
file4 
file5 
file6 

sent 294 bytes received 31 bytes 650.00 bytes/sec 
total size is 0 speedup is 0.00 (DRY RUN) 
[jesse@localhost test]$ rsync -av --dry-run sdir/ --compare-dest=/home/jesse/test/tdir/mon/ /home/jesse/test/tdir/tue/ /home/jesse/test/tdir/wed/ --backup-dir=/home/jesse/test/tdir/thu/ 
sending incremental file list 
./ 
file6 

sent 208 bytes received 22 bytes 460.00 bytes/sec 
total size is 0 speedup is 0.00 (DRY RUN) 
[jesse@localhost test]$ rsync -av --dry-run sdir/ --compare-dest=/home/jesse/test/tdir/mon/ /home/jesse/test/tdir/tue/ /home/jesse/test/tdir/wed/ /home/jesse/test/tdir/thu/ --backup-dir=/home/jesse/test/tdir/thu/ 
sending incremental file list 
./ 
file3 
file4 
file5 
file6 

sent 294 bytes received 31 bytes 650.00 bytes/sec 
total size is 0 speedup is 0.00 (DRY RUN) 
[jesse@localhost test]$ rsync -av sdir/ --compare-dest=/home/jesse/test/tdir/mon/ /home/jesse/test/tdir/tue/ /home/jesse/test/tdir/wed/ /home/jesse/test/tdir/thu/ --backup-dir=/home/jesse/test/tdir/thu/ 
sending incremental file list 
./ 
file3 
file4 
file5 
file6 

sent 438 bytes received 95 bytes 1,066.00 bytes/sec 
total size is 0 speedup is 0.00 
[jesse@localhost test]$ tree 
. 
├── sdir 
│ ├── file1 
│ ├── file2 
│ ├── file3 
│ ├── file4 
│ ├── file5 
│ └── file6 
└── tdir 
    ├── fri 
    ├── mon 
    │ ├── file1 
    │ └── file2 
    ├── thu 
    │ ├── file3 
    │ ├── file4 
    │ ├── file5 
    │ └── file6 
    ├── tue 
    │ └── file3 
    └── wed 
     ├── file3 
     ├── file4 
     └── file5 

7 directories, 16 files 
[jesse@localhost test]$ 

Answer 1

我注意到，rsync手册页明确指出“开始在2.6.4版本中，多--link-dest目录可以提供”，并有一个类似的说明为--compare-dest但不是--backup-dir（这是有道理的）。如果你想限制你的备份“只有不在其他目录之一中的东西”，--*-dest选项是要走的路。

这里是我的测试和结果：

$ mkdir src mon tue wed 
$ for n in {1..3}; do date > src/file$n; sleep 1; done 
$ rsync -avi src/ mon/ 
building file list ... done 
.d..t.... ./ 
>f+++++++ file1 
>f+++++++ file2 
>f+++++++ file3 

sent 346 bytes received 92 bytes 876.00 bytes/sec 
total size is 87 speedup is 0.20 
$ for n in {4..5}; do date > src/file$n; sleep 1; done 
$ rsync -avi --compare-dest=$PWD/mon/ src/ tue/ 
building file list ... done 
.d..t.... ./ 
>f+++++++ file4 
>f+++++++ file5 

sent 295 bytes received 70 bytes 730.00 bytes/sec 
total size is 145 speedup is 0.40 
$ for n in {6..7}; do date > src/file$n; sleep 1; done 
$ rsync -avi --compare-dest=$PWD/mon/ --compare-dest=$PWD/tue/ src/ wed/ 
building file list ... done 
.d..t.... ./ 
>f+++++++ file6 
>f+++++++ file7 

sent 319 bytes received 70 bytes 778.00 bytes/sec 
total size is 203 speedup is 0.52 
$ 

这里的显着区别是，比较目录的每个需要自己选择。记号是不是：

rsync --compare-dest one/ two/ src/ dest/ 

而是：

rsync --compare-dest=one/ --compare-dest=two/ src/ dest/ 

为了把这个成被每天运行的代码，你可以尝试类似如下（未经测试脚本）：

#!/usr/bin/env bash 

# Store our rsync arguments in an array, for easier handling. 
rsync_args=(-a) 

# If we're running interactively, show us rsync verbose output. 
if [ -t 0 ]; then 
    rsync_args+=(-vi) 
fi 

# Step through weekdays, adding days to our argument list, stopping at "today" 
read today < <(date '+%a') 
for day in Mon Tue Wed Thu Fri; do 
    [ "$day" = "$today" ] && break 
    rsync_args+=(--compare-dest=$PWD/${day,,}) 
done 

# And finally, copy everything. 
rsync "${rsync_args[@]}" src/ "${day,,}"/ 

请注意，参数扩展（${s,,}和${s^^}）中的bash案例控件是bash版本4的特性。