是否有一个简单的命令组合可以计算两个目录结构之间不同的文件的总大小？
diff我正在考虑以某种方式发送to的输出du，但我不够熟练，不知道如何实际执行此操作。
一个例子：
/foo-a/
bar/
test1.txt 12 bytes 01/01/2000 12:00:00
test2.txt 12 bytes 01/01/2000 12:00:00
test3.txt 12 bytes 01/01/2000 12:00:00
test4.txt 12 bytes 01/01/2000 12:00:00
test5.txt 12 bytes 01/01/2000 12:00:00
/foo-b/
bar/
test1.txt 12 bytes 01/01/2000 12:00:00
test2.txt 12 bytes 01/01/2000 12:00:05
test3.txt 35 bytes 01/01/2000 12:00:05
test6.txt 12 bytes 01/01/2000 12:00:00
test7.txt 12 bytes 01/01/2000 12:00:00
在上面，比较两个目录，b我a想：
test1.txt: unchanged, same size: 0 bytes
test2.txt: changed, same size: 12 bytes
test3.txt: changed, different size: 35 bytes
test4.txt: unchanged, same size: 0 bytes
test5.txt: deleted: 0 bytes
test6.txt: hardlink of test4.txt: 0 bytes
test7.txt: added: 12 bytes
total: 59 bytes