Shell脚本以递归方式比较目录 [英] Shell script to compare directories recursively

问题描述

我在几个月前使用的外部硬盘驱动器上备份了文件服务器，此后该文件服务器已关闭。自那时以来，大多数数据已恢复到使用的临时文件服务器上，但存在一些不一致之处。

I have a file server backup on an external hard drive a few months old for a file server that went down since then. Most of the data was recovered onto a temporary file server thats been in use since then but there are some inconsistencies.

我将挂载外部并将其与当前数据同步，但是首先我需要建立在较新副本上已更新的文件。

I am going to mount the external and rsync it with the current data to it but first I need to establish files that have gotten updated on the newer copy.

我可以做diff -r -q / old / / new /来获得这个，我试图在脚本方面做得更好，所以我试图写一些东西来重命名旧的

I can do diff -r -q /old/ /new/ to obtain this, I am trying to get better at scripting so I am trying to write something that will rename the old file to filename.old whenever diff returns a difference.

推荐答案

因此，在检查后，我无法在 diff 仅输出文件名差异，因此我们将处理diff输出。

So after checking, I wasn't able to find an option in diff to only output the filename differences so we'll just work with what diff outputs.

如果 diff 查找不同的文件，输出如下所示：

If diff finds files that differ, the output is something like this:

Files old/file and new/file differ

由于您的所有bash脚本都会从中重命名更改后的文件旧目录，我们要从此输出中提取 old / file 。让我们从仅显示 Files ... differ 这样的行开始（可能会生成其他行）：

Since all your bash script would be doing is renaming the changed file from the old directory, we want to extract old/file from this output. Let's start by only displaying lines like Files...differ (as other lines may be produced):

diff -rq old/ new/ | grep "^Files.*differ$"

现在您将只获得如前所示的行。下一步是获取文件名。您可以使用 awk 来完成此操作，方法是添加 awk'{print $ 2}'作为另一个管道，但是如果文件名本身包含空格，awk会将其分解为两个单独的字符串。我们将改用sed：

Now you'll only get lines like the one shown before. Next step is getting the filename. You can do this with awk by adding something like awk '{print $2}' as another pipe but if the filename itself contains spaces, awk will break up that as two separate strings. We'll use sed instead:

diff -rq old/ new/ | grep "^Files.*differ$" | sed 's/^Files \(.*\) and .* differ$/\1/'

现在，这将生成旧目录中已更改文件的列表。使用简单的for循环，您现在可以重命名每个文件：

Now this will produce a list of files that have changed in the old directory. Using a simple for loop, you can now rename each of the files:

for old_file in `diff -rq old/ new/ | grep "^Files.*differ$" | sed 's/^Files \(.*\) and .* differ$/\1/'`
do
   mv $old_file $old_file.old
done

就是这样！

编辑：实际上，那是不是全部。对于包含空格的文件，此循环仍然会失败，因此请稍作讨论。 for 会尝试生成一个默认情况下用空格分隔的列表。让我们将其更改为使用换行符：

edit: actually, that's not all. This loop still fails on files with spaces so let's muck with it a bit. for will try to produce a list separated by a space by default. Let's change this to use newlines instead:

OLD_IFS=$IFS
# The extra space after is crucial
IFS=\

for old_file in `diff -rq old/ new/ | grep "^Files.*differ$" | sed 's/^Files \(.*\) and .* differ$/\1/'`
do
   mv $old_file $old_file.old
done
IFS=$OLD_IFS

此临时替换bash的默认分隔符（ $ IFS ）到换行符，并在完成循环后将其放回去，这样就不会按空格分割。

This temporarily replaces bash's default separator ($IFS) to a newline and puts it back after it's done with the loop so you don't split by space.

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