Copier trop grand fichier Commmand Linux

/media/LACIE sounds like you're handling a pre-formatted drive, most likely with the FAT32 filesystem. According to Wikipedia, the maximum file size for FAT32 is about 4GB.

I suggest to reformat the drive to either ext4 (for supporting Linux file permissions) or NTFS (if you need to share the drive with windows users).
bilalahmed_dev