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November 14, 2005 12:00 AM

Embedding Double Quotes in the Command

Windows IT Pro
InstantDoc ID #48219
Rating: (1)

The Windows Script Host (WSH) runtime engine reads a script's command-line arguments and makes them accessible in the WshArguments object and its associated collections. The command-line parser uses the double quote (") character as an argument delimiter; that is, an argument can contain spaces if it's enclosed in double quotes. This presents a problem, however, if the argument itself needs to contain double quotes, because the parser doesn't have a built-in way of embedding the " character. For example, suppose you want to execute the following RunProgram.vbs command line:

RunProgram.vbs
  "C:\Program Files\Test Program\Test.exe
  C:\Program Files\Test.txt"

Windows Management Instrumentation's (WMI's) Win32_Process Create method might successfully execute the program (C:\Program Files\Test Program\Test.exe), but the parameter (C:\Program Files\Test.txt) contains spaces and should be quoted so that Test.exe recognizes it as a single parameter. RunProgram.vbs uses VBScript's Unescape function to work around this problem. It takes a string that contains %xx character sequences (where xx is the hex value of an ASCII character) and replaces them with their ASCII character equivalents. The double quote is ASCII character 34 (hex 22), so you'd type the following command instead:

RunProgram.vbs "%22C:\Program Files\Test Program\Test.exe%22
  %22C:\Program Files\Test.txt%22"

This approach won't work if the command line you want to use actually contains %xx character sequences, but such sequences should be sufficiently rare that the suggested technique should work in most cases.

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Comments
  • Ronald
    3 years ago
    Nov 24, 2009

    To get the whole argument string including double quotes:

    Function GetArguments

    Dim oWMI, oScript, cScripts, aSplit

    Set oWMI = GetObject("winmgmts:{impersonationLevel=impersonate}!\\\\.\\root\\cimv2")
    Set cScripts = oWMI.ExecQuery("select * from win32_process where name='wscript.exe' or name='cscript.exe'")
    For Each oScript in cScripts
    aSplit = Split(oScript.CommandLine, " """ & WScript.ScriptFullName & """ ", 2)
    If UBound(aSplit) > 0 Then GetArguments = Trim(aSplit(1))
    Next

    End Function

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