4

cmp(1) will of course tell me if the contents of two files are identical, but in order to test restoring from backups I also wanted to compare the relevant (!) file attributes.

So if I did something simple like

mv foo.bar foo.bar.save
deja-dup --restore foo.bar # or some other backup tool

how do I compare the attributes of foo.bar and foo.bar.save and test for sufficient equality in a shell script (or similar). I can do

stat foo.bar{,.save}

and manually inspect the output remembering to ignore inode, atime, and ctime (as well as link count, for some reason?), but this is error prone. Is there a cmp-with-attributes tool somewhere which include SELinux and other attributes? Must work on Fedora and ext4 file systems; ideally on "all" systems. Do I need to hack something up in perl?

(No point having backups if you don't test that they work right.)

  • 1
    stat has two options, -c or --format, and --printf, that you can use to make it print the data you are interested in, in the format you want, so you can later compare it with diff or another tool. – angus Aug 29 '12 at 9:03
6
getallattr() {
  lsattr -d -- "$1" | cut -d ' ' -f1
  getfattr -dm- -- "$1" | tail -n +2 | sort
  stat -c '%u %g %a %s %x %y' -- "$1"
}

To retrieve all the attributes (at least those that can easily be restored). You could also include the md5sum in there.

And then do

diff <(getallattr file1) <(getallattr file2)

(ksh93, zsh, bash syntax).

  • "getfattr -dm -" already takes care of ACLs, so no need for an extra command. – Stéphane Chazelas Aug 30 '12 at 5:29

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