Trickle FTP connection

Question

I have a script for backing up my data. The last line is:

echo "$FTPConnectstring
$FTPCommands
bye" | ftp -ivn

It works great, but I wish I could 'trickle' this (i.e. limit upload bandwidth usage). I tried many command lines like these:

echo "$FTPConnectstring
$FTPCommands
bye" | ftp -ivn | trickle -s -u 4096

but ftp transfer seems to execute with no BW usage limit I also tried something like this

FinalCommand=$(echo -e "$FTPConnectstring\n$FTPCommands\nbye")
trickle -s -u 4096 ftp -ivn ${FinalCommand}

but this one doesn't connect ftp correctly...

Any help appreciated !!

Answer 1

In your first attempt, you only trickle the standard output from ftp (depending on the implementation, probably just the progress messages, if even that). In your second attempt, you have a syntax error; the argument to ftp should be a host name, not a command sequence. Try this instead:

echo -e "$FTPConnectstring\n$FTPCommands\nbye" |
trickle -s -u 4096 ftp -ivn

If the ftp binary is statically linked, trickle can't override its socket-handling internals; but in that case, you can probably switch to a different FTP client such as ncftp which should also behave better with scripting.