Executing a command stored in a variable from PowerShell - powershell

Question

I have a command that I have build and stored in a variable in PowerShell. This command works if I do a Write-Host and copy and paste into a standard cmd.exe window.
How do I execute this command from inside my script?
I have tried several combination of Invoke-Command or Invoke-Expression with no luck.
This is how I built the variable:
$cmd1 = $arcprg + $arcdir + "\" + $site1 + "-" + $hst + "-" + $yesterday + ".zip " + $logpath1 + "u_ex" + $yesterday + ".log"
This is what the variable looks like if it is printed to the screen:
7z.exe a -tzip c:\arc_logs\site-host-at-web1-100827.zip c:\inetpub\logs\logfiles\w3svc1\u_ex100827.log

Answer 1

Here is yet another way without Invoke-Expression but with two variables
(command:string and parameters:array). It works fine for me. Assume
7z.exe is in the system path.
$cmd = '7z.exe'
$prm = 'a', '-tzip', 'c:\temp\with space\test1.zip', 'C:\TEMP\with space\changelog'
& $cmd $prm
If the command is known (7z.exe) and only parameters are variable then this will do
$prm = 'a', '-tzip', 'c:\temp\with space\test1.zip', 'C:\TEMP\with space\changelog'
& 7z.exe $prm
BTW, Invoke-Expression with one parameter works for me, too, e.g. this works
$cmd = '& 7z.exe a -tzip "c:\temp\with space\test2.zip" "C:\TEMP\with space\changelog"'
Invoke-Expression $cmd
P.S. I usually prefer the way with a parameter array because it is easier to
compose programmatically than to build an expression for Invoke-Expression.

Answer 2

Try invoking your command with Invoke-Expression:
Invoke-Expression $cmd1
Here is a working example on my machine:
$cmd = "& 'C:\Program Files\7-zip\7z.exe' a -tzip c:\temp\test.zip c:\temp\test.txt"
Invoke-Expression $cmd
iex is an alias for Invoke-Expression so you could do:
iex $cmd1
For a full list :
Visit https://ss64.com/ps/ for more Powershell stuff.
Good Luck...