linux - Persistent non-interactive FTP session for usage in shell scripts -

i script complex scenario of file transfers linux windows ftp server (detecting new/changed files , transfer) , unable find command-line ftp client supports sending files on persistent (one time login) session on non-interactive mode.

ssh/scp password-less authentication not option, since have no access windows ftp server.

for example using lftp

`lftp -u user,pass -p 21 -e "mput newfile.txt;"` 10.0.0.100  

will upload file server, requires authentication/handshaking happen on every request, takes long time , severely slows down transfers.

i wondering whether there way authenticate once, establish persistent connection , sending files on connection. lftp , other clients able in interactive mode (connect , perform multiple commands until quitting).

therefore:

• is there ftp client on linux may operate in non-interactive mode?
• alternatively, there way simulate behaviour, scripting on interactive mode? maybe utilizing expect netcat/telnet and/or named pipes?

untested, can tcl:

package require ftp set conn [ftp::open server user pass] while true {     after 5000          ;# sleep 5 seconds     foreach newfile [glob -nocomplain *] {         puts "sending $newfile"         ftp::put $newfile         file delete $newfile     } } 

the expect similar. untested:

set timeout -1 spawn lftp -u user,pass server expect "> " while true {     sleep 5     foreach newfile [glob -nocomplain *] {         puts "sending $newfile"         send "put $newfile\r"         expect "> "         file delete $newfile     }     send "\r"          ;# "hit enter" keep-alive }