How to use FTP via the command line to download all files

Why use Automator when you can stay in bash?

I found a really cool little script called appify that will instantly turn other scripts into actual applications. You can try it a few times to observe its behavior. Since you already use bash, I am hoping that this answer as an alternative to exactly what you are asking for is acceptable. 

The idea is to split your script into 3 distinct scripts:

---

1: start ftp service on preferred network interface only

 #!/bin/bash
 #start ftp service
 #sudo="/usr/bin/sudo"
 #launchctl="/bin/launchctl"
 say="/usr/bin/say"
 networksetup="/usr/sbin/networksetup"
 tail="/usr/bin/tail"
 head="/usr/bin/head"
 cut="/usr/bin/cut"
 curl="/usr/bin/curl"
 currentInterface=$(networksetup -listnetworkserviceorder |tail +2 |head -n1 |cut -c5-12)
 getExternaladdress=$(curl ipecho.net/plain)
 SiriSays="say -v Samantha"
 #sudo -s launchctl load -w /System/Library/LaunchDaemons/ftp.plist 
 #your command will start ftp on all network interfaces
 if [ "$currentInterface" = "Airport" ]; 
      then
           networksetup -setpassiveftp Airport on
      else
           networksetup --setpassiveftp Ethernet on
 fi
 $SiriSays "ftp service has been initiated for the"
 echo $currentInterface |$SiriSays; $SiriSays "interface"
 $SiriSays "Your external IP address is"
 echo $getExternaladdress | $SiriSays
 exit

---

2: stop ftp service

 #!/bin/bash
 #stop ftp service
 #sudo="/usr/bin/sudo"
 #launchctl="/bin/launchctl"
 networksetup="/usr/sbin/networksetup"
 say="/usr/bin/say"
 tail="/usr/bin/tail"
 head="/usr/bin/head"
 cut="/usr/bin/cut"
 currentInterface=$(networksetup -listnetworkserviceorder |tail +2 |head -n1 |cut -c5-12)
 SiriSays="say -v Samantha"
 #sudo -s launchctl unload -w /System/Library/LaunchDaemons/ftp.plist
 #your command requires sudo
 if [ "$currentInterface" = "Airport" ]; 
      then
           networksetup -setpassiveftp Airport off
      else
           networksetup -setpassiveftp Ethernet off
 fi
 $SiriSays "ftp service has been terminated"
 exit

---

3: check ftp service status

 #!/bin/bash
 #check ftp service status
 networksetup="/usr/sbin/networksetup"
 say="/usr/bin/say"
 tail="/usr/bin/tail"
 head="/usr/bin/head"
 cut="/usr/bin/cut"
 currentInterface=$(networksetup -listnetworkserviceorder |tail +2 |head -n1 |cut -c5-12)
 SiriSays="say -v Samantha"
 if [ "$currentInterface" = "Airport" ]; 
      then
           networksetup -getpassiveftp Airport |$SiriSays
      else
           networksetup -getpassiveftp Ethernet |$SiriSays
 fi
 exit

Then apply the appify script to them

What you're left with is three little apps to put in your dock that, when launched, will start or stop the ftp service on your preferred network interface, or tell you what's up with ftp, respectively, and should not require any admin password. I only had time to test the first one, so if they don't work as I hope they do, then you can comment out or delete my logic and use your launchctl method.

---

Unison is my go-to tool for a bi-directional file sync. (Mac binaries are available on a contributor's site.) I tend to think of it as a more interactive, configurable, and bi-directional version of rsync. Since it's a good *nix citizen, it can be automated via your favorite method. It's open-source and has ports to major OS platforms.

Unfortunately, Unison is no longer under active development, which may or may not be an issue for you. (I think the last time I used it was under 10.6.) But, it does fit your requirements nicely:

• It handles bi-directional sync and works great on large files and data sets.
• It can run in a completely automated way or interactively (where your review and confirm every change).
• It runs over SSH.
• GUI and CLI interfaces are available. (FWIW, the Mac GUI version, while nice/convenient, was always slightly flaky for me.)
• Its end-user documentation is excellent and thorough.
• It has configuration options for a multitude of use cases.
• It has a design principle of leaving things in a Good State at all times, which makes it easier to recover should the connection be lost at any time.

And here's the main selling point for using it (for me, at least):

For remote SSH targets, it logs into the remote machine, runs a separate copy of Unison there to scan for changes, and then reconciles the state with your local machine to only transmit the bits (or bytes :-)) that differ, much like rsync does. This makes it very efficient with bandwidth, and it's also able to maintain caches of its file index on each side to make subsequent scans faster. For large data sets, this is a huge deal.

There are other Mac-specific tools for file synchronization, but, IIRC, they tend to assume that the filesystem is local, and are either very inefficient with bandwidth or very presumptuous about file "changes" (metadata, actual data) on large remote files / data sets.

Unison worked the way I needed it to, was reliable, and made me confident in using it due to its great documentation. Thank you, Benjamin C. Pierce!