You’re passing a parameter to invoke-expression in your function that looks like:
.\PsExec.exe \\my-PC -s -h -nobanner powershell.exe Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* | Out-File C:\Temp\Software.txt
When psexec.exe tries to parse the text above, it splits it using the ‘space’ character as a delimiter. So it recognizes the following command options:
It accepts \my-pc as the -computername command option, -s as another command option, …
until it comes across HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall* and it errors out since it cannot match it to one of the command options it’s looking for.
On the other hand using
.\PsExec.exe \\my-PC -s -h -nobanner powershell.exe "Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* | Out-File C:\Temp\Software.txt"
gets parsed into
"Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* | Out-File C:\Temp\Software.txt"
which is accepted by psexec.exe parser - it can match each of these strings to a command option…
Usage: psexec [\\computer[,computer2[,...] | @file]][-u user [-p psswd][-n s][-r servicename][-h][-l][-s|-e][-x][-i [session]][-c [-f|-v]][-w directory][-d][-<priority>][-a n,n,...] cmd [arguments]
-a Separate processors on which the application can run with
commas where 1 is the lowest numbered CPU. For example,
to run the application on CPU 2 and CPU 4, enter:
-c Copy the specified program to the remote system for
execution. If you omit this option the application
must be in the system path on the remote system.
-d Don't wait for process to terminate (non-interactive).
-e Does not load the specified account's profile.
-f Copy the specified program even if the file already
exists on the remote system.
-i Run the program so that it interacts with the desktop of the
specified session on the remote system. If no session is
specified the process runs in the console session.
-h If the target system is Vista or higher, has the process
run with the account's elevated token, if available.
-l Run process as limited user (strips the Administrators group
and allows only privileges assigned to the Users group).
On Windows Vista the process runs with Low Integrity.
-n Specifies timeout in seconds connecting to remote computers.
-p Specifies optional password for user name. If you omit this
you will be prompted to enter a hidden password.
-r Specifies the name of the remote service to create or interact.
-s Run the remote process in the System account.
-u Specifies optional user name for login to remote
-v Copy the specified file only if it has a higher version number
or is newer on than the one on the remote system.
-w Set the working directory of the process (relative to
-x Display the UI on the Winlogon secure desktop (local system
-arm Specifies the remote computer is of ARM architecture.
-priority Specifies -low, -belownormal, -abovenormal, -high or
-realtime to run the process at a different priority. Use
-background to run at low memory and I/O priority on Vista.
computer Direct PsExec to run the application on the remote
computer or computers specified. If you omit the computer
name PsExec runs the application on the local system,
and if you specify a wildcard (\\*), PsExec runs the
command on all computers in the current domain.
@file PsExec will execute the command on each of the computers listed
in the file.
cmd Name of application to execute.
arguments Arguments to pass (note that file paths must be
absolute paths on the target system).
-accepteula This flag suppresses the display of the license dialog.
-nobanner Do not display the startup banner and copyright message.