FTP

• Command Line Syntax
• FTP's Interactive Commands
• Creating Unattended FTP Scripts
• Summary
• Alternatives
  • WGET
  • WinSCP
  • ScriptFTP

I used to get many questions about unattended FTP scripts.

On this page I will show some examples of unattended FTP download (or upload, the difference in script commands is small) scripts.

Command Line Syntax

The -s switch is the most valuable switch for batch files that take care of unattended downloads and uploads:
FTP -s:ftpscript.txt
On some operating systems redirection may do the same:
FTP < ftpscript.txt
However, unlike the -s switch its proper functioning cannot be guaranteed.

FTP's Interactive Commands

The following table shows the FTP commands available in Windows NT 4. The difference with other operating systems is marginal.
The actual commands available can be found by starting an FTP session and then typing a question mark at the FTP> prompt.
To get a short description af a particular command, type a question mark followed by that command: (user input shown in bold italics):

Creating Unattended FTP Scripts

Suppose an interactive FTP session looks like this (user input shown in bold italics):

An FTP script for unattended file transfer would then look like this:

USER MyUserId
MyPassword
cd files/pictures
binary
prompt n
mget *.*

Note that I left out the BYE (or QUIT) command, it isn't necessary to specify this command in unattended FTP scripts (though it doesn't do any harm either).

As you can see, using a script like this is a potential security risk: the password is stored in the script in a readable form.

As Tom Lavedas once pointed out in the alt.msdos.batch newsgroup, it is safer to create the script "on the fly" and delete it afterwards:

@ECHO OFF
:: Check if the password was given
IF "%1"=="" GOTO Syntax
:: Create the temporary script file
> script.ftp ECHO USER MyUserId
>>script.ftp ECHO %1
>>script.ftp ECHO cd files/pictures
>>script.ftp ECHO binary
>>script.ftp ECHO prompt n
>>script.ftp ECHO mget *.*
:: Use the temporary script for unattended FTP
:: Note: depending on your OS version you may have to add a '-n' switch
FTP -v -s:script.ftp ftp.myhost.net
:: For the paranoid: overwrite the temporary file before deleting it
TYPE NUL >script.ftp
DEL script.ftp
GOTO End

:Syntax
ECHO Usage: %0 password

:End

Sometimes it may be necessary to make the script completely unattended, without the user having to know the password, or even the user ID, but with the possibility to check for errors during transfer.
There are several ways to do this.
One is to redirect FTP's output to a log file and either display it to the user or use FIND to search the log file for any error messages.
Another way to do this, on the fly, is by displaying FTP's output on screen, in the mean time using FIND /V to hide the output you do not want the user to see (like the password and maybe even the USER command):

FTP -s:script.ftp ftp.myhost.net | FIND /V "USER" | FIND /V "%1"

It is important not to use FTP's -v switch in either case.

Summary

To create a semi interactive FTP script, you may need to split it into several smaller parts, like an unattended FTP script to read a list of remote files, the output of which is redirected to a temporary file, which in turn is used by a batch file to create a new unattended FTP script on the fly to download and/or delete some of these files.

Create these files by writing down every command and all screen output in an interactive FTP session, analyze this "log" thoroughly, and test, test, and test again!

And don't forget to log the results by redirecting the script's output to a log file. You may need it later for debugging purposes...

Alternatives

Instead of Windows' own native FTP command, you can choose from a multitude of "third party" alternatives.
I'll discuss three of those alternatives here: a command-line tool, a GUI-tool and VBScript with a third party ActiveX component.

WGET

WGET is a port of the UNIX wget command.

WGET is perfect for anonymous FTP or HTTP downloads (sorry, no uploads), but it can be used for downloads requiring authentication too.

GNU WGET comes with help both in the (text mode) console and in Windows Help format.

The basic syntax for an FTP download doesn't get any simpler than this:

WGET ftp://ftp.mydomain.com/path/file.ext

for anonymous downloads, or:

WGET ftp://user:password@ftp.mydomain.com/path/file.ext

when authentication is required.

WinSCP

WinSCP is a free open-source SFTP and FTP client with a command line/scripting interface as well as a GUI.

WinSCP can be used for uploads and downloads.

ScriptFTP

ScriptFTP is a tool to, you may have guessed, automate FTP file transfers.
It supports plain FTP, FTPS and SFTP protocols.
Commands to e-mail and/or log results are available.
All commands can be run on the command line or from a script.

Scripts can be encrypted, or converted online to self-contained executables.

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