[SOLVED] [lost+found] command cp not working

thomasbb · 01-03-2021, 10:00 AM

My usb stick is formatted in ext4 (the command mount -t vfat wasn't found at that moment). But when I want to copy everything from it, the cp command fails because of the lost+found directory.
Is there a way to bypass the error? For example, I tried

Code:

mount -v /dev/sdXY /mnt
cp /mnt/* ~/mydir 2> /dev/null
cp /mnt/* ~/mydir 2> /dev/null 1>&2

but it's not enough... Any idea?

michaelk · 01-03-2021, 11:40 AM

The lost+found directory is used by the fsck utility to copy corrupted and orphaned files. It is owned by root and a regular user does not have permissions to access the directory. When an ext filesystem is created the lost+found directory is also created in the filesystems "root" directory.

There is no need to copy the lost+found directory but everything else should still copy ok.

aiszisz · 01-03-2021, 11:44 AM

Could you post the outputs of mount and cp?
Of course without the 2 > /dev/null

lost+found should be hidden as far as I know and hidden files are not copied by cp

computersavvy · 01-03-2021, 11:56 AM

Quote:

Originally Posted by aiszisz

Could you post the outputs of mount and cp?
Of course without the 2 > /dev/null

lost+found should be hidden as far as I know and hidden files are not copied by cp

I think that you will find this applies to lost+found everywhere.

drwx------. 2 root root 16384 Feb 23 2018 lost+found

It is not hidden and cannot be copied by anyone except root. It should not ever be needed unless a device is failing. It only applies to the device/filesystem where found so should never be needed in any other form.

thomasbb · 01-03-2021, 12:20 PM

Quote:

Originally Posted by michaelk

The lost+found directory is used by the fsck utility to copy corrupted and orphaned files. It is owned by root and a regular user does not have permissions to access the directory. When an ext filesystem is created the lost+found directory is also created in the filesystems "root" directory.

There is no need to copy the lost+found directory but everything else should still copy ok.

The command cp /mnt/* ~/mydir stops after copying the first file, but if I try to copy the files one by one it works

Quote:

Originally Posted by aiszisz

Could you post the outputs of mount and cp?
Of course without the 2 > /dev/null

lost+found should be hidden as far as I know and hidden files are not copied by cp

It's on another computer I just turned off... Maybe tomorrow I answer your question

Quote:

Originally Posted by computersavvy

I think that you will find this applies to lost+found everywhere.

drwx------. 2 root root 16384 Feb 23 2018 lost+found

It is not hidden and cannot be copied by anyone except root. It should not ever be needed unless a device is failing. It only applies to the device/filesystem where found so should never be needed in any other form.

Maybe it's because the user is in the wheel group?

pan64 · 01-03-2021, 12:33 PM

2>/dev/null does not bypass any error, just suppresses the error message.
You ought to try rsync instead of cp, if you wish to skip/ignore directories (like lost+found).

michaelk · 01-03-2021, 01:04 PM

Quote:

The command cp /mnt/* ~/mydir stops after copying the first file, but if I try to copy the files one by one it works

Then you might have permission and/or other problems.

As a quick test I created a disk image formatted as ext4 and created a few files owned by my user.

A cp /mnt/test/* /destination copied everything except the lost+found directory and the output was just a warning
cp: omitting directory ‘/mnt/test/lost+found’

thomasbb · 01-04-2021, 10:55 AM

Quote:

Originally Posted by michaelk

Then you might have permission and/or other problems.

Today it all goes well... Maybe I was doing the copy with root or with a sudo? Thank you for taking the time to try

thomasbb · 01-04-2021, 10:58 AM

Quote:

Originally Posted by pan64

2>/dev/null does not bypass any error, just suppresses the error message.

Understood

Quote:

Originally Posted by pan64

You ought to try rsync instead of cp, if you wish to skip/ignore directories (like lost+found).

It's for a few config files but thanks for the rsync command, one day I need to give it a try

ondoho · 01-05-2021, 03:49 AM

Quote:

Originally Posted by thomasbb

Is there a way to bypass the error? For example, I tried

Code:

mount -v /dev/sdXY /mnt
cp /mnt/* ~/mydir 2> /dev/null
cp /mnt/* ~/mydir 2> /dev/null 1>&2

but it's not enough... Any idea?

Remove the 2> /dev/null 1>&2 and 2> /dev/null!
then add the -v option to cp:

Code:

cp -v /mnt/* ~/mydir
cp -v /mnt/* ~/mydir

BTW, cp does not copy recursively until you tellit to do so. In other words, this will only copy single files, not directories with something in them.

Code:

man cp

thomasbb · 01-05-2021, 05:17 AM

Quote:

Originally Posted by ondoho

Remove the 2> /dev/null 1>&2 and 2> /dev/null!
then add the -v option to cp:

It didn't work at that time, maybe I was doing the cp with sudo or root?
But yesterday, everything was ok