Conditional Processing in Automation

Particularly for complex conditions or conditions involving remote files, using WinSCP .NET assembly is the easiest and the recommended approach.

An example of PowerShell script that checks if a remote file exists before downloading it:

$remotePath = "/home/user/test.txt"
$localPath = "C:\download\test.txt"
 
if ($session.FileExists($remotePath))
{
    Write-Host "File $remotePath exists, downloading"
    $session.GetFiles($remotePath, $localPath).Check()
}
else
{
    Write-Host "File $remotePath does not exist"
}

See also:

• Checking file existence;
• Downloading files from FTP/SFTP server only after “done” file is created;
• Using WinSCP .NET assembly from PowerShell;
• Example for Session.FileExists (complete code for above example);
• Example Checking file existence and timestamp (showing how to test a local and a remote file existence and how to compare local and remote file timetamps).

If you do not want to use .NET assembly, for simple conditions or conditions involving local files, you may be able to move the condition outside of WinSCP script into a wrapper batch file.

For example you can use an if command to test a local file existence before uploading it:

if exist c:\upload\test.txt winscp.com /ini=nul /log=upload.log /script=upload.txt

If you need different conditions for individual script commands, you can generate the WinSCP script file on the fly step by step:

@echo off
set FILE1=c:\upload\test.txt
set FILE2=c:\other\file.txt
 
(
  echo open sftp://user:password@example.com/ -hostkey="ssh-rsa 2048 xxxxxxxxxxx..."
  if exist %FILE1% echo put %FILE1%
  if exist %FILE2% echo put %FILE2%
  echo exit
) > upload.txt
 
winscp.com /ini=nul /log=upload.log /script=upload.txt

See also:

• Checking file existence;
• Downloading files from FTP/SFTP server only after “done” file is created;
• Checking script results;
• Advanced FTP/SFTP scripting;
• Interpreting XML log for advanced scripting.