I've been banging my hand on this one for quite a while now.

I am trying to send a file by ftp under bash with one command line, or at least to give before hand the login and password of the ftp connexion.

I managed something with ncftp but not everyone has it so If anyone has the slightest idea what to do please let me know.

(he should be able to send a file without ANY user assistance)

I do something like this:

ftp -n <remote.send

The remote.send file has any ftp commands you like. I'm using it to archive a weeks worth of backups on a remote server:

open ftp.mydomain.com
user myuser password
binary
delete file6.tgz
rename file5.tgz file6.tgz
rename file4.tgz file5.tgz
rename file3.tgz file4.tgz
rename file2.tgz file3.tgz
rename file1.tgz file2.tgz
rename file.tgz file1.tgz
lcd /var/www/html/forum/cron
put file.tgz
quit