Ny ftp command to resume upload

Usually, ftp command line clients support the configuration file ~/.netrc where you can configure credentials for remote systems, e.g.:

machine legacy.system.example.org
login juser
password keins

When you ftp legacy.system.example.org then you don't have to retype this information anymore.

If you need to do more automation, you can script ftp via piping commands into it, e.g.:

$ cat pushit.sh
# complex logic to set
# EXAMPLE_FILE=
ftp <<EOF
prompt
mput $EXAMPLE_FILE
quit
EOF

Sure, if the system does not support ssh, it probably does not support ftps either - but you can try it (e.g. via ftp-ssl) if you need to secure your connection.

LFTP

An alternative to one of the plain ftp commands is to use lftp, since it provides several features to automated login and command execution.

Example:

$ lftp -e 'source ~/login.lftp'
$ cat login.lftp
open sftp://juser:geheim@backup.example.net
cd /path/to/favorite/dir

Note that this example shows automated password authentication to a SFTP server which is not supported by the standard OpenSSH sftp client.

The option -e instructs lftp to execute the commands at startup and stay interactive.

Of course, such a lftp script mach also source other scripts, and also automatically disconnect from the server.

In contrast, with -c or -f lftp directly exits after executing the commands specified as argument or read from the specified file.

With zsh:

autoload zfinit
zfinit
zmodload zsh/datetime

files=N*.TXT
zfopen $host $user $passwd &&
  zfcd $remotedir &&
  zfrglob files &&
  for f ($files) {
    t=$EPOCHREALTIME
    strftime -s ts %H%M%S ${t%.*}
    ts=$ts.${t#*.}
    zfgcp -Gt $f N_$ts.TXT
  }
zfclose