Executing a Command stored in a Variable from Powershell

Question

I have a command that i have build and stored in a variable in power shell. This command works if i do a write-host and copy and past 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

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

Answer 2

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.