How to safely copy files to a flash drive on Linux
If you copy files to a USB flash drive and remove it right after cp finishes, data may still be in the kernel write cache. That means copy command is done, but device writes are not fully done yet. The safe approach is simple: Copy files Force data to disk Unmount device Remove flash drive Basic safe flow cp -r ./my-folder /mnt/usb/ sync umount /mnt/usb Linux vs Windows write cache behavior On Linux, if you run umount without sync first, umount may take a while....