SFTP with Powershell in a batch script

I've got a batch script which runs via schtasks every night on different remote Windows PCs (Windows 7 32-bit SP1). These PCs need to FTP files to and from a Linux server. Currently using FTP, the batch script works just fine.

Now the Linux servers are being changed over to use only SFTP. I'd like to write a short PowerShell script to SFTP the same files to/from the server – I've got Posh-Ssh installed to use in PowerShell on these Windows systems (PS Version 5.1).

Currently the part of the batch script doing the FTP looks like this:

REM make temp file for FTP
echo open pos%STORE%               >  C:\temp\temp.txt
echo username                      >> C:\temp\temp.txt
echo password                      >> C:\temp\temp.txt
echo ascii                         >> C:\temp\temp.txt    
echo cd /path/to/use               >> C:\temp\temp.txt
echo put %USERDOMAIN%.ftp          >> C:\temp\temp.txt
echo put posdaily.txt posdaily.ftp >> C:\temp\temp.txt
echo get prod.txt                  >> C:\temp\temp.txt
echo get posdaily.ftp              >> C:\temp\temp.txt
echo quit                          >> C:\temp\temp.txt

REM **** FTP to put/get files from POS Server ****
echo First Try Connect to POS ....
ftp -iv -s:\temp\temp.txt >> C:\log\Daily.log  2>&1

Is there a way to use this same temp.txt that's being created to pass the username/password/put/get to a PowerShell script that uses Posh-Ssh? What changes would I need to make to the temp.txt file?

I can call a separate batch script which runs the PowerShell script – I've done that in previous batch scripts – but I'm not sure how to write the PowerShell script – what command/commands would I use in the PowerShell script to use the data in temp.txt?

If I get it working in PowerShell, I should be able to put a call to this same PowerShell script in a C# and VB script that need to do that same thing.