I have been trying to update my SSM agent. I'm running the command AWS updatessmagent

Solution 1:

According to AWS documentation for Windows, manual updates to SSM agent are done manually. It looks like the powershell commands are

Invoke-WebRequest `
  https://s3.amazonaws.com/ec2-downloads-windows/SSMAgent/latest/windows_amd64/AmazonSSMAgentSetup.exe `
-OutFile $env:USERPROFILE\Desktop\SSMAgent_latest.exe

Start-Process `
  -FilePath $env:USERPROFILE\Desktop\SSMAgent_latest.exe `
  -ArgumentList "/S"

rm -Force $env:USERPROFILE\Desktop\SSMAgent_latest.exe

You can also set up automatic SSM agent updates as described here.

I suspect the command you ran was for Linux.