File permissions change when transfering between external drives and laptop

I noticed a few years ago that when I transfer files back and forth between my laptop and my external drive all the files that I have transfered have changed permissions.

I format all my external drives as exFAT so I can use larger files.

Why does this happen?

Is there a better way to keep the file permissions intact when transfering files back and forth between external drives?

The test file: Fantastic Fungi (2019).mkv

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This is what the file permssions looks like before I transfer it to my external hard drive

ls -l

-rw-r–r-- 1 user user 577761580 May 2 2024 ‘Fantastic Fungi (2019).mkv’

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This is what the file permssions looks like after I transfer it back to my laptop

ls -l

-rwxr-xr-x 1 user user 577761580 May 2 2024 ‘Fantastic Fungi (2019).mkv’

When I right click file permissions dialogue box. The “Allow this file to run as a program” is ticked.

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The way have overcome this is to run a simple one liner to reset the permissions for directories and files.

Open a terminal in the directory of the folders and files you want to change

All directories will be 775. All files will be 664

find . -type d -exec chmod 0755 {} ;

find . -type f -exec chmod 0644 {} ;

Directory permission 0755 is similar to “drwxr-xr-x”

File permission 0644 is equal to “-rw-r–-r–-“.

-type d = directories

-type f = files

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  • SavvyWolf@pawb.socialEnglish
    24·
    3 hours ago

    Exfat does not support permissions, so when it gets moved to the drive, that information is lost.

    If permission information is important to you and compatibility with non-linux devices isn’t, you can reformat the device as ext4 to support all linux features.

    • infjarchninja@lemmy.mlOP
      31·
      2 hours ago

      Thank you SavvyWolf

      This is particularly annoying when I have to upgrade my distro and all my files have to be moved to an external drive.

      Unfortunately some of my files are up to 10Gb. thats why I stayed with exFAT.

      I will certainly try Ext4 on my external drives.

      • Eideen@lemmy.world
        61·
        2 hours ago

        Try compressing it in to a tar, this will save permissions.

        you can also use backup tools like “Pika backup” (borg backup).

        • infjarchninja@lemmy.mlOP
          1·
          2 hours ago

          Thank you Eideen

          I have never used any back up programs, Maybe I should consider it.

          Both Borg and Pike-backup are in the offical repos (extra).

          I shall check them out

  • Eugenia@lemmy.mlEnglish
    10·
    3 hours ago

    This is absolutely normal. FAT/exFAT do not support unix permissions (let alone Linux ext4’s any special flags etc). So each time you copy files there, the permissions and all other flags are lost or get bad in general.

    To save your permissions you have two options:

    1. Zip/targzip or xz your linux files before you copy them on your fat drives. Preferably on files that overall aren’t larger than 1 gb, just to avoid other weird problems.

    2. Use ext4 on your external drives.

    • infjarchninja@lemmy.mlOP
      2·
      3 hours ago

      Thank you Eugenia

      Compressisng the files sounds a great idea.

      I have in fact compressed a 12Gb file that I split into 10Gb chunks that still decompresses without problems.

      This is particularly annoying when I have to upgrade my distro and all my files have to be moved to an external drive.

      Unfortunately some of my files are up to 10Gb. thats why I stayed with exFAT.

      I will certainly try Ext4 on my external drives. I will test it this week

  • MonkderVierte@lemmy.zip
    1·
    2 hours ago

    Thunars “allow this file to run as a program” is generally bugged. Always set to on for me on files like xml, md, json, so they execute on single-click instead of opening the default action. chmod -x doesn’t change that checkmark either or only sometimes.

    Btw, any file manager that is similiar in features (custom actions) and look but less crashy.

  • Hack3900@lemy.lol
    3·
    3 hours ago

    ExFat doesn’t support file permissions so a default value is used, I believe you can only change the permissions at mount time

  • nyan@sh.itjust.works
    2·
    3 hours ago

    exFAT is a Microsoft creation that (unsurprisingly) doesn’t understand or preserve Linux-style file permissions. Neither did any of the FAT varieties before it. So the permissions on the files when you get them back relate to the mount options you pass to the exFAT drive (in this case, you probably want to set dmask and fmask), or the permissions on the directory it’s mounted to.

    If you don’t want to twiddle with mount options, you could reformat the external disks using Linux-native filesystems like ext4, but you’ll lose the ability to mount them on Windows if you do that.

    • infjarchninja@lemmy.mlOP
      1·
      2 hours ago

      Thank you nyan

      I will look into the dmask and fmask mount options.

      Definitely a no! in regards to attaching my drives to any windows machine.

      The last windows machine I turned on was a Windows 95 machine when they first came out.

      I thank god, That I wouldnt even know how to turn on a windows 10 or 11 surveillance machine.

    • N0x0n@lemmy.ml
      1·
      3 hours ago

      but you’ll lose the ability to mount them on Windows if you do that.

      One viable solution to that, is to mount that drive as SMB share, best of the two worlds !