How to suppress quotes in PowerShell commands to executables

Question

Is there a way to suppress the enclosing quotation marks around each command-line argument that PowerShell likes to generate and then pass to external executables for command-line arguments that have spaces in them?

Here's the situation:

One way to unpack many installers is a command of the form:

msiexec /a <packagename> /qn TARGETDIR="<path to folder with spaces>"

Trying to execute this from PowerShell has proven quite difficult. PowerShell likes to enclose parameters with spaces in double-quotes. The following lines:

msiexec /a somepackage.msi /qn 'TARGETDIR="c:\some path"'

msiexec /a somepackage.msi /qn $('TARGETDIR="c:\some path"')

$td = '"c:\some path"'

msiexec /a somepackage.msi /qn TARGETDIR=$td

All result in the following command line (as reported by the Win32 GetCommandLine() API):

"msiexec" /a somepackage.msi /qn "TARGETDIR="c:\some path""

This command line:

msiexec /a somepackage.msi TARGETDIR="c:\some path" /qn

results in

"msiexec" /a fooinstaller.msi "TARGETDIR=c:\some path" /qn

It seems that PowerShell likes to enclose the results of expressions meant to represent one argument in quotation marks when passing them to external executables. This works fine for most executables. However, MsiExec is very specific about the quoting rules it wants and won't accept any of the command lines PowerShell generates for paths have have spaces in them.

Is there a way to suppress this behavior?

Nope, nothing worked. Powershell simply can't do this. I resorted to having the script call a batch file that would quote it properly. — David Gladfelter, Jun 10 '10 at 23:08

score 8 · Answer 1 · answered Apr 13 '10 at 05:25

8

Escape the inner quotes like this:

msiexec /a somepackage.msi TARGETDIR=`"c:\some path`" /qn

answered Apr 13 '10 at 05:25

stej

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Hooray! This works if you can include the string literally. What if you have it as a variable, i.e. `$target_dir='c:\some path'` ? – Jason R. Coombs Aug 20 '11 at 20:36
@JasonR.Coombs then you would need to do `Targetdir = `"$target_dir`"` – JNK Apr 18 '12 at 17:00

Chris Towles · Answer 2 · 2010-10-22T19:11:46.753

6

Here is a function I use to better handle multiple arguments and those with spaces and quotes. Note that to the code blocks below don't color where strings start and end correctly and you have to use ` to escape quotes you want in the parameter.

function InstallMSIClient{
$Arguments = @()
$Arguments += "/i"
$Arguments += "`"$InstallerFolder\$InstallerVerFolder\Install.msi`""
$Arguments += "RebootYesNo=`"No`""
$Arguments += "REBOOT=`"Suppress`""
$Arguments += "ALLUSERS=`"1`""
$Arguments += "/passive"

Write-Host "Installing $InstallerVerFolder."
Start-Process "msiexec.exe" -ArgumentList $Arguments -Wait }

There's a more complete example on my blog. [http://www.christowles.com]

edited Oct 22 '10 at 19:11

answered Oct 22 '10 at 18:48

Chris Towles

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This answer was immensely helpful. It led me to the answer for my own purposes, which was the only answer I could find which accepted MSI parameters from Powershell variables. – Jason R. Coombs Aug 20 '11 at 21:25
Yes, this was extremely helpful. I had a parameter with multiple nested quotation marks which PS would just parse correctly. – Paweł Czopowik Jun 25 '15 at 16:28

score 0 · Answer 3 · edited Sep 16 '18 at 22:56

0

Put the entire argument in quotes and escape the inner quotes. Otherwise PowerShell will try to parse it:

msiexec /a <packagename> /qn 'TARGETDIR=\"<path to folder with spaces>\"'

edited Sep 16 '18 at 22:56

Peter Mortensen

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answered Apr 12 '10 at 22:21

zdan

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score 0 · Answer 4 · answered May 18 '10 at 20:04

I don't have the answer, but this guy seems to be onto something.
http://www.eggheadcafe.com/software/aspnet/33777311/problem-escaping-command.aspx

I couldn't make it work for me.

Here's someone else reporting the issue too: _http://powershell.com/cs/forums/p/2809/3751.aspx

Here's another idea by someone: _http://www.roelvanlisdonk.nl/?p=1135

That didn't work for me either...

score 0 · Answer 5 · answered Jul 23 '10 at 02:24

I don't have the answer, but this guy seems to be onto something. http://www.eggheadcafe.com/software/aspnet/33777311/problem-escaping-command.aspx

Yeah, it looks like they found a solution at the end:

Finally worked out how to do this using invoke-expression:

$installprop = "TARGETDIR=" + "```"" + $installpath + "```""

invoke-expression "msiexec /i $packagepath $installprop"

I would recommend using a here-string though to avoid having to do all the escaping.

$command = @'
msiexec /a <packagename> /qn TARGETDIR="<path to folder with spaces>"
'@

invoke-expression $command

I could not get this to work in a powershell script on Powershell 2.0. I tried the first technique (because I have my $installpath as a variable), but msiexec pops up the help indicating the parameters are invalid. — Jason R. Coombs, Aug 20 '11 at 21:06

score 0 · Answer 6 · edited Sep 16 '18 at 22:58

I've just hit the problem. The following worked for me:

&cmd /c "msiexec /i `"$appName.msi`" /l* `"$appName.msi.log`" /quiet TARGETDIR=`"D:\Program Files (x86)\$appName\`""

The key was executing cmd rather than msiexec directly. This had two benefits:

I could wrap the entire msiexec command in a string, so it would resolve the the $appName variable while still using the backtick to escape the quotes around TARGETDIR.
I was able to make use of $LastExitCode to check success/failure of the msiexec operation. For some reason $LastExitCode isn't set when calling msiexec directly (hat-tip: http://www.powergui.org/thread.jspa?threadID=13022)

How to suppress quotes in PowerShell commands to executables

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