How can I non-recursively migrate directories with Perl or shell?

Question

Hello,

We're migrating home folders to a new filesystem, and I am looking for a way to automate it using Perl or a shell script. I don't have much choice in programming languages as the systems are proprietary storage clusters that should remain as unchanged as possible.

Task: Under directory /home/ I have various users' home folders aaa, bbb, ccc, ... and they have certain permissions and user/group ownership that need to remain intact upon migration to /newhome/. Here's example of what needs to be migrated from /home:

drwxr-xr-x    3 aaaaa    xxxxxxxxx   4096 Feb 26  2008 aaaaa/
drwxrwxrwx   88 bbbbbbb  yyyyyy      8192 Dec 16 16:32 bbbbbbb/
drwxr-xr-x    6 ccccc    yyyyyy      4096 Nov 24 04:38 ccccc/
drwxr-xrwx   36 dddddd   yyyyyy      4096 Jun 20  2008 dddddd/
drwxr-xr-x   27 eee      yyyyyy      4096 Dec 16 02:56 eee/

So, exact same folders with permissions and ownerships should be created under /newhome. Copying/moving files should not be a concern, as it will be handled later.

Anyone has worked on such script? I am really new to Perl, so I need help.

Answer 1

cp's -a flag will maintain permission, modification times etc. You should for be able to do something like:

for a in `ls /home`; do cp -a "/home/$a" "/newhome/$a" ; done

Try it with one directory to see if does what you need before automating it.

EDIT: You can disable recursive file copying by using rsync or tar as mentioned by Paul. With rsync, subdirectories are still preserved, but files aren't copied:

sudo rsync -pgodt /home/ /newhome/

I haven't tried tar's --no-recursion, so can't comment on it.

EDIT 2: Another way

find /home/ -maxdepth 1 -print | sudo cpio -pamVd /newhome

Reference

Answer 2

This will create the directories and copy all the files.

cd /home; tar cvBf - . | (cd /newhome; tar xvpBf -)

If you don't want to copy all the files, you might be able to do that by adding a "--no-recursion" to the first tar command.

Answer 3

If these directories are on the same filesystem, why not simply

cp -p /home/* /newhome/

Answer 4

You can only preserve the owner and group if you do the copying operation as root. Most of the commands given will work - the tar and the cp -rp options will.

The only trick to worry about is non-writable directories, but that's an issue for non-root users. Then, I tend to use:

(cd /home; find . -depth) | cpio -pvdumB /newhome

The -depth option means that file and sub-directories are processed before the directories themselves, so the no-write permission on the directory is only set after all the contents of the directory have been copied into it. You can also use a 'sort -r' to list files in reverse order, which ensures that directories appear after their contents.