[Samba] Copy with curl ? force user ignored?

[Gilles]

I found how to get Samba to create files on a removable device formated 
as VFAT 1) as the account set by "guest account", and 2) with rw r r:

==================
cat /etc/fstab
#Linux takes care of converting literals into matching uid/guid in 
/etc/passwd
UUID=439E-8C29 /mnt/sdcard     vfat 
uid=www-data,gid=www-data,dmask=000,fmask=0133,user       0 0

systemctl stop smb
umount /mnt/sdcard
chown -R www-data:www-data /mnt/sdcard
ll /mnt/
systemctl daemon-reload
mount /mnt/sdcard/
mount
systemctl start smb
c:\>copy test.txt \\linux\share
ll /mnt/
==================

https://unix.stackexchange.com/questions/87494/can-fstab-options-uid-and-gid-be-the-user-group-name-or-must-they-be-numeric