Exported functions:
- Invoke-SshCommand run a command on a Linux guest via ssh.exe (BatchMode=yes)
- Copy-SshItem scp a local path to a remote path (or vice versa)
- Test-SshReady test TCP:22 + ssh echo round-trip
Used by Wait-VMReady.ps1 -Transport SSH, Invoke-RemoteBuild.ps1 -GuestOS Linux,
Get-BuildArtifacts.ps1 -GuestOS Linux.