Contents:

• http://www.gnu.org/software/bash/manual/bashref.html#Quoting
• http://linux.about.com/library/cmd/blcmdl1_bash.htm

• The Exec Key
  http://library.gnome.org/devel/desktop-entry-spec/#exec-variables
• The GOption commandline parser
  http://library.gnome.org/devel/glib/stable/glib-Commandline-option-parser.html

• Bash Cheat Sheet: https://www.pcwdld.com/bash-cheat-sheet

• ShowParams.c
  • #include "stdafx.h"
    int main(int argc, char* argv[])
    {
      for (int i = 0; i < argc; ++i)
      {
        printf("param %d = ",i);
        puts(argv[i]);
        printf("\n");
      }
      return 0;
    }
    
    
    (Note: Avoid using printf when printing parameters, as the parameter may contain a % which would be interpreted by printf as a conversion specifier. The program may crash with a bizarre error, such as "runtime error R6002 - Floating point not loaded".)
    
    
    
    (Note: If we started this function with wmain or _tmain then argv[] would point to wide character (unicode) strings. [Technically I'm not sure if they are UTF-16LE or UCS-2. I have 2 old posts discussing the basics of Unicode:
    

    • • Overview of Unicode's five different standards:
         http://forums.multiedit.com/viewtopic.php?f=4&t=1717#p6178
      
    • • Unicode: The Programmer's Nightmare
         http://forums.multiedit.com/viewtopic.php?f=4&t=1717#p6270

    I also wrote a short book on Unicode:

    • • Brief Introduction to Unicode

• ShowParams.cpp

  • It's difficult to get the Windows Console to display Unicode characters, so here's a C++ WinForms program that will display the arguments in a TextBox.

    // ShowParams.cpp : main project file.
    #include "stdafx.h"
    #include "Form1.h"
    
    using namespace ShowParams2;
    
    [STAThreadAttribute]
    int main(array<System::String ^> ^args)
    {
      // Enabling Windows XP visual effects before any controls are created
      Application::EnableVisualStyles();
      Application::SetCompatibleTextRenderingDefault(false); 
    
      // Create the main window and run it
      Application::Run(gcnew Form1(args));
      return 0;
    }
    
    
    // Form1.h
    #pragma once
    
    namespace ShowParams2 {
    
      using namespace System;
      using namespace System::Windows::Forms;
    
      public ref class Form1 : public System::Windows::Forms::Form
      {
      public:
      private:
        array<System::String ^> ^args;
      public:
        Form1(array<System::String ^> ^_args) : args(_args)
        {
          InitializeComponent();
        }
    
      protected:
        ~Form1()
        {
          if (components)
          {
            delete components;
          }
        }
      private: System::Windows::Forms::TextBox^  textBox1;
      protected: 
    
      private:
        System::ComponentModel::Container ^components;
    
    #pragma region Windows Form Designer generated code
        void InitializeComponent(void)
        {
          this->textBox1 = (gcnew System::Windows::Forms::TextBox());
          this->SuspendLayout();
          // 
          // textBox1
          // 
          this->textBox1->Anchor = static_cast<System::Windows::Forms::AnchorStyles>((((System::Windows::Forms::AnchorStyles::Top | System::Windows::Forms::AnchorStyles::Bottom) 
            | System::Windows::Forms::AnchorStyles::Left) 
            | System::Windows::Forms::AnchorStyles::Right));
          this->textBox1->Location = System::Drawing::Point(12, 12);
          this->textBox1->Multiline = true;
          this->textBox1->Name = L"textBox1";
          this->textBox1->Size = System::Drawing::Size(260, 238);
          this->textBox1->TabIndex = 0;
          // 
          // Form1
          // 
          this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
          this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
          this->ClientSize = System::Drawing::Size(284, 262);
          this->Controls->Add(this->textBox1);
          this->Name = L"Form1";
          this->Text = L"Form1";
          this->Load += gcnew System::EventHandler(this, &Form1::Form1_Load);
          this->ResumeLayout(false);
          this->PerformLayout();
    
        }
    #pragma endregion
      private: System::Void Form1_Load(System::Object^  sender, System::EventArgs^  e) {
          int i = 0;
          for each(String^ arg in args)
          {
            textBox1->AppendText("arg[" + i + "]=" + arg + Environment::NewLine);
            i++;
          }
        }
    
      };
    }
    
    

• ShowParamsC#.cs
  • using System;
    
    namespace ShowParams
    {
        class Program
        {
            static void Main(string[] args)
            {
                Console.WriteLine("There are {0} program arguments", args.Length);
    
                foreach (string arg in args)
                {
                    Console.WriteLine(arg);
                }
            }
        }
    }

• ShowParams.bat
  • @echo off
    echo Param1 = %1
    echo Param2 = %2
    echo Param3 = %3

• ShowParams.vbs
  • If Wscript.Arguments.Count = 0 Then
            Wscript.echo "No parameters found"
    Else
        i=0
            Do until i = Wscript.Arguments.Count
            Parms = Parms & "Param " & i & " = " & Wscript.Arguments(i) & " " & vbcr
            i = i+1
            loop
            Wscript.echo parms
    End If

1. ShowParams.exe
   

   ShowParams.exe (written in c)
   >ShowParams.exe "c:\test a\" "c:\test b\" param 0 = ShowParams.exe param 1 = c:\test a" c:\test param 2 = b"

   ( \" is interpreted as meaning 'a literal double quote.')
   
   
2. C#ShowParams.exe
   

   C#ShowParams.exe (written in C#)
   >C#ShowParams.exe "c:\test a\" "c:\test b\" There are 2 program arguments c:\test a" c:\test b"

   ( \" is interpreted as meaning 'a literal double quote.')
   
   
3. ShowParams.bat
   

   ShowParams.bat (a batch file)
   >ShowParams.bat "c:\test a\" "c:\test b\" param 1 = "c:\test a\" param 2 = "c:\test b\"

   (the double quotes are included as part of the parameter)
   
   
4. ShowParams.vbs
   

   ShowParams.vbs (a Visual Basic script)
   >ShowParams.vbs "c:\test a\" "c:\test b\" param 0 = c:\test a\ param 1 = c:\test b\

   (The double quotes are removed from the parameter)

1. ShowParams.exe
   

   ShowParams.exe     and     C#ShowParams.exe cmdline = "ShowParams.exe Hello Goodbye Friday"            ↓           CreateProcess(cmdline)  →     → New Process running ShowParams.exe            ↓ call           GetCommandLine()            ↓ parse           argv[] = ShowParams.exe Hello Goodbye Friday

   
   The parameter parsing rules are determined by the C++ compiler that compiled ShowParams.exe
   
   
   
2. ShowParams.bat
   

   ShowParams.bat cmdline = "ShowParams.bat Hello Goodbye Friday"            ↓           CreateProcess(cmdline)  →     → New Process runs cmd.exe to process the batch file ShowParams.bat            ↓ call           GetCommandLine()            ↓ parse           %1 = Hello %2 = Goodbye %3 = Friday

   
   The parameter parsing rules are determined by cmd.exe which processes the batch file.
   
   
   
3. ShowParams.vbs
   

   ShowParams.vbs cmdline = "ShowParams.vbs Hello Goodbye Friday"            ↓           CreateProcess(cmdline)  →     → New Process runs WScript.exe to process the VBScript file ShowParams.vbs            ↓ call           GetCommandLine()            ↓ parse           Wscript.Arguments(0) = Hello Wscript.Arguments(1) = Goodbye Wscript.Arguments(2) = Friday

   
   The parameter parsing rules are determined by WScript.exe which processes the VBScript file.

1. Parameters passed to ShowParams.exe are parsed by ShowParams.exe . The parameter parsing rules are determined by the C++ compiler that compiled ShowParams.exe
2. Parameters passed to ShowParams.bat are parsed by cmd.exe which is the program that processes batch files.
3. Parameters passed to ShowParams.vbs are parsed by WScript.exe which is the program that processes VBScript files³

• There is separate documentation for each version of Microsoft's C/C++ compiler.
• Fortunately the documentation is identical for all of them.
• Unfortunately the documentation isn't complete.
• The implementation changed in 2008, which isn't documented.
• Fortunately you're reading this.

  Note: The Rules Changed in 2008

1. Arguments are delimited by white space, which is either a space or a tab.
2. The caret character (^) is not recognized as an escape character or delimiter. The character is handled completely by the command-line parser in the operating system before being passed to the argv array in the program.
   They are referring to the scenario discussed in sec. 6.2 below, where first the command line parser (cmd.exe) parses your command, handling such things as the escape character ^ , the redirection characters > & < , the pipe character | , the %  character which may identify environment variables that need to be expanded (e.g. %PROGRAMFILES%), etc. The rules here describe how your C/C++ executable will parse the lpCommandLine that was passed to CreateProcess() by cmd.exe or whoever calls CreateProcess().
3. A string surrounded by double quotation marks ("string") is interpreted as a single argument, regardless of white space contained within. A quoted string can be embedded in an argument.
   The double quotes don't have to be around the whole parameter. A double quoted part may occur anywhere in the parameter.
4. A double quotation mark preceded by a backslash (\") is interpreted as a literal double quotation mark character (").
5. Backslashes are interpreted literally, unless they immediately precede a double quotation mark.
6. If an even number of backslashes is followed by a double quotation mark, one backslash is placed in the argv array for every pair of backslashes, and the double quotation mark is interpreted as a string delimiter.
   This includes any trailing double quote enclosing a parameter.
7. If an odd number of backslashes is followed by a double quotation mark, one backslash is placed in the argv array for every pair of backslashes, and the double quotation mark is "escaped" by the remaining backslash, causing a literal double quotation mark (") to be placed in argv.
8. The missing undocumented rule has to do with how doubledouble quotes ("") are handled:
   • Prior to 2008:
     If a closing " is followed immediately by another ", the 2nd " is accepted literally and added to the parameter.
   • After 2008
     1. A double quote encountered outside a double quoted block starts a double quoted block.
     2. A double quote encountered inside a double quoted block:
        • not followed by another double quote ends the double quoted block.
        • followed immediately by another double quote (e.g. ""), a single double quote is added to the output, and the double quoted block continues.

1. Parameters are always separated by a space or tab (multiple spaces/tabs OK)
   
2. If the parameter does not contain any spaces, tabs, or double quotes, then all the characters in the parameter are accepted as is (there is no need to enclose the parameter in double quotes).
   
3. Enclose spaces and tabs in a double quoted part
   
4. A double quoted part can be anywhere within a parameter
   
5. 2n backslashes followed by a " produce n backslashes + start/end double quoted part
   
6. 2n+1 backslashes followed by a " produce n backslashes + a literal quotation mark
   
7. n backslashes not followed by a quotation mark produce n backslashes
   
8. undocumented rules regarding double quotes:
   
   Prior to 2008:

   • A " outside a double quoted block starts a double quoted block
   • A " inside a double quoted block ends the double quoted block
   • If a closing " is followed immediately by another ", the 2nd " is accepted literally and added to the parameter.
   Post 2008:
   • Outside a double quoted block a " starts a double quoted block.
   • Inside a double quoted block a " followed by a different character (not another ") ends the double quoted block.
   • Inside a double quoted block a " followed immediately by another " (i.e. "") causes a single " to be added to the output, and the double quoted block continues.

The following algorithm was reverse engineered by disassembling a small C program compiled using Microsoft Visual C++ and examining the disassembled code.

(post 2008)

See msvcr100dparsing.htm for the actual diasssembled code with annotations.



(2020: Thank you to Pepa Stefan for noting an error in the earlier version of the diagram.)

(pre 2008)

See msvcrtparsing.htm for the actual diasssembled code with annotations.

note if odd number of backslashes, we ignore last backslash and begin again.

1.	Parse off parameter 0 (the program filename)
	•	The entire parameter may be enclosed in double quotes (it handles double quoted parts) (Double quotes are necessary if there are any spaces or tabs in the parameter)
	•	There is no special processing of backslashes (\)
2.	Parse off next parameter:
	a.	Skip over multiple spaces/tabs between parameters
		LOOP
	b.	Count the backslashes (\). Let m = number of backslashes. (m may be zero.)
		IF even number of backslashes (or zero)
	c.	IF next character following m backslashes is a double quote:
			Even number of backslashes?
			Yes. If we're not in a double quoted part, " begins a double quoted part.
			Yes. If we're in a double quoted part, "" skip 1st take 2nd "
			If m is even (or zero)
				if currently in a double quoted part
					IF next character is also a "
						move to next character (the 2nd ". This character will be added to the parameter.)
					ELSE
						set flag to not add this " character to the parameter
						toggle double quoted part flag (end double quoted part)
					ENDIF
				else
						set flag to not add this " character to the parameter
				endif
			Endif
		ENDIF
		ENDIF
		Add backslashes to output
		m = m/2 (floor divide e.g. 0/2=0, 1/2=0, 2/2=1, 3/2=1, 4/2=2, 5/2=2, etc.)
	d.	add m backslashes
	e.	add this character to our parameter
		ENDLOOP

1. by the Command Prompt Window (cmd.exe)
2. by ShowParams.exe

Note: The result is what gets passed as part of the lpCommandLine argument to the CreateProcess() API. The newly created process still needs to retrieve the lpCommandLine string and parse off the parameters using it's own parsing rules (e.g. if it's a C/C++ program, it will use the Microsoft C/C++ parameter parsing rules to create the argv[] vector. See Putting It Together below for more on this).

A command line passed to a C/C++ program passes through two parsers:

1. The cmd.exe command line parser parses your command & parameters
2. The C/C++ program retrieves the resulting command line and parses off the parameters

Here are some examples:

It gets harder when double quotes are not escaped with ^ as cmd.exe will now interpert them as “Start or end a double quoted part.”

A Simplified method: (2016) (updated 2019)

The trick is to enclose parameters with ^" instead of just "

e.g. instead of:

use

The command processor cmd.exe will strip off the ^ and won't start any double quoted parts.

Simplified method steps:

Example 8.1:     Bed Bath & Beyond		Parameter
Start with the parameter you want (parameter includes spaces)		Bed Bath & Beyond
1.	Search for any "	no " in parameter
2.	Escape with ^ all special characters: ^ < > | & ( ) " i.e. replace  ^  with  ^^      replace  <  with  ^<      replace  >  with  ^>      replace  |  with  ^|      replace  &  with  ^&      replace  (  with  ^(      replace  )  with  ^)      replace  "  with  ^"	Bed Bath ^& Beyond            ↑
3.	double the number of trailing \	no trailing \
4.	Add a leading and trailing ^"	^"Bed Bath ^& Beyond^" ↑↑                  ↑↑
5.	If this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:		^"Bed Bath ^& Beyond^"
Now examine how this parameter gets parsed:
A.	cmd.exe treats ^ as escape character. cmd.exe finds no double quoted parts because all " are escaped with ^ cmd.exe removes escape character ^	^"Bed Bath ^& Beyond^" ↓          ↓        ↓
B.	cmd.exe passes this to the C/C++ program	"Bed Bath & Beyond"
C.	C/C++ program parses string starting at the beginning. C/C++ program encounters initial " and starts a double quoted part. The " is removed.	┌──────  "Bed Bath & Beyond"  ↓
D.	C/C++ program copies characters to output parameter until it encounters closing " The double quoted part ends and the " is removed.	┌─────────────────┐   Bed Bath & Beyond"                    ↓
E.	C/C++ program encounters space (or end of string) after parameter. Since we are no longer in a double quoted part, parser declares this is the end of the parameter.	┌─────────────────┐   Bed Bath & Beyond                    ↓
F.	Result is the desired parameter we started with	Bed Bath & Beyond

Sample Test File:

• TestParams8_1.bat
  • 
    ShowParams.exe ^"Bed Bath ^& Beyond^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

Example 8.1b: Command Line to C/C++ Program

Example 8.1b:     Bed Bath & Beyond\		Parameter
Start with the parameter you want (parameter includes spaces)		Bed Bath & Beyond\
1.	Search for any "	no " in parameter
2.	Escape with ^ all special characters: ^ < > | & ( ) " i.e. replace  ^  with  ^^      replace  <  with  ^<      replace  >  with  ^>      replace  |  with  ^|      replace  &  with  ^&      replace  (  with  ^(      replace  )  with  ^)      replace  "  with  ^"	Bed Bath ^& Beyond\            ↑
3.	double the number of trailing \	Bed Bath ^& Beyond\\                     ↑↑
4.	Add a leading and trailing ^"	^"Bed Bath ^& Beyond\\^" ↑↑                    ↑↑
5.	If this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:		^"Bed Bath ^& Beyond\\^"
Now examine how this parameter gets parsed:
A.	cmd.exe treats ^ as escape character and removes them. cmd.exe finds no double quoted parts because all " are escaped with ^	^"Bed Bath & Beyond\\^" ↓                    ↓
B.	cmd.exe passes this as parameter to the C/C++ program	"Bed Bath & Beyond\\"
C.	C/C++ program sees the first double quote as beginning a double quoted part. This double quote is not added to the parameter.	┌──────────────   Bed Bath & Beyond\\"
D.	C/C++ program copies characters to the output parameter. When it encounters the \ it finds two \ followed by a " • Two is an even number • We are currently in a double quoted part • The character following the " is not another " → Therefore two/2=1 backslashes are added to the parameter → and the " ends the double quoted part	┌──────────────────┐   Bed Bath & Beyond\                    ↑
E.	Result is the desired parameter we started with	Bed Bath & Beyond\

Sample Test File:

• TestParams8_1b.bat
  • 
    ShowParams.exe ^"Bed Bath ^& Beyond\\^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

Now examine what would happen if we had only one backshash at the end instead of two:
A.	cmd.exe treats ^ as escape character and removes them. cmd.exe finds no double quoted parts because all " are escaped with ^	^"Bed Bath & Beyond\^" ↓                   ↓
B.	cmd.exe passes this as parameter to the C/C++ program	"Bed Bath & Beyond\"
C.	C/C++ program sees the first double quote as beginning a double quoted part	┌──────────────   Bed Bath & Beyond\"
D.	C/C++ program copies characters to the output parameter. When it encounters the \ it finds one \ followed by a " • One is an odd number → One/2=0 so no backslashes are added to the parameter • We are currently in a double quoted part → Therefore the " is added to the parameter. The double quoted part continues.	┌────────────────────   Bed Bath & Beyond"                    ↑
E.	If there was more following this it would be considered a part of the same parameter. If the command line abruptly ends, the parameter is accepted as is, even though the double quoted part wasn't closed properly.	Bed Bath & Beyond"

Example 8.1c: Command Line to C/C++ Program

Example 8.1c:     Bed Bath \\\ Beyond		Parameter
Start with the parameter you want (parameter includes spaces)		Bed Bath \\\ Beyond
1.	Search for any "	no " in parameter
2.	Escape with ^ all special characters: ^ < > | & ( ) " i.e. replace  ^  with  ^^      replace  <  with  ^<      replace  >  with  ^>      replace  |  with  ^|      replace  &  with  ^&      replace  (  with  ^(      replace  )  with  ^)      replace  "  with  ^"	no special characters in parameter
3.	double the number of trailing \	no trailing \
4.	Add a leading and trailing ^"	^"Bed Bath \\\ Beyond^" ↑↑                   ↑↑
5.	If this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:		^"Bed Bath \\\ Beyond^"
Now examine how this parameter gets parsed:
A.	cmd.exe treats ^ as escape character and removes them. cmd.exe finds no double quoted parts because all " are escaped with ^	^"Bed Bath \\\ Beyond^" ↓                    ↓
B.	cmd.exe passes this as parameter to the C/C++ program	"Bed Bath \\\ Beyond"
C.	C/C++ program sees the first double quote as beginning a double quoted part. This double quote is not added to the parameter.	┌────────   Bed Bath \\\ Beyond"
D.	C/C++ program copies characters to the output parameter. Parser comes to the \\\ followed by a space → Since \\\ is not followed by a " they are copied as is.	┌────────────   Bed Bath \\\ Beyond"
E.	Parser comes to the " → We are in a double quoted part, so parser checks to see if there's another " immediately following, which there is not, so this " ends the double quoted part and the " is not added to the parameter.	┌───────────────────┐   Bed Bath \\\ Beyond"                      ↓
E.	Result is the desired parameter we started with	Bed Bath \\\ Beyond

Sample Test File:

• TestParams8_1c.bat
  • 
    ShowParams.exe ^"Bed Bath \\\ Beyond^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

Example 8.2:     Bed "Bath" & Beyond		Parameter
Start with the parameter you want (parameter includes spaces)		Bed "Bath" & Beyond
1.	Search for any " Double the number of \ immediately preceding any " (there are none) Then add one more \ before each "	Bed \"Bath\" & Beyond       ↑     ↑
2.	Escape with ^ all special characters: ^ < > | & ( ) "
	i.e. replace  ^  with  ^^      replace  <  with  ^<      replace  >  with  ^>      replace  |  with  ^|      replace  &  with  ^&      replace  (  with  ^(      replace  )  with  ^)      replace  "  with  ^"	Bed \^"Bath\^" ^& Beyond        ↑      ↑  ↑
3.	double the number of trailing \	no trailing \
4.	Add a leading and trailing ^"	^"Bed \^"Bath\^" ^& Beyond^" ↑↑                        ↑↑
5.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:		^"Bed \^"Bath\^" ^& Beyond^"
Now examine how this parameter gets parsed:
A.	cmd.exe treats ^ as escape character and removes them. cmd.exe finds no double quoted parts because all " are escaped with ^	^"Bed \^"Bath\^" ^& Beyond^" ↓      ↓      ↓  ↓        ↓
B.	cmd.exe passes this as parameter to the C/C++ program	"Bed \"Bath\" & Beyond"
C.	C/C++ program sees this as a double quoted parameter. Note that all " inside the parameter are escaped with \	┌─────────────────────┐  "Bed \"Bath\" & Beyond"  ↓                     ↓
D.	C/C++ program applies the rule 2n+1 backslashes followed by a " produce n backslashes + a literal quotation mark. \" becomes " (for n=0)	Bed \"Bath\" & Beyond       ↓     ↓
E.	Result is the desired parameter we started with	Bed "Bath" & Beyond

Sample Test File:

• TestParams8_2.bat
  • 
    ShowParams.exe ^"Bed \^"Bath\^" ^& Beyond^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

Example 8.3:     Bed Bath & \"Beyond"		Parameter
Start with the parameter you want (parameter includes spaces)		Bed Bath & \"Beyond"
1.	Search for any " Double the number of \ immediately preceding any " Then add one more \ before each "	Bed Bath & \\\"Beyond\"              ↑↑↑       ↑
2.	Escape with ^ all special characters: ^ < > | & ( ) "
	i.e. replace  ^  with  ^^      replace  <  with  ^<      replace  >  with  ^>      replace  |  with  ^|      replace  &  with  ^&      replace  (  with  ^(      replace  )  with  ^)      replace  "  with  ^"	Bed Bath ^& \\\^"Beyond\^"            ↑     ↑        ↑
3.	double the number of trailing \	no trailing \
4.	Add a leading and trailing ^"	^"Bed Bath ^& \\\^"Beyond\^"^" ↑↑                          ↑↑
5.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:		^"Bed Bath ^& \\\^"Beyond\^"^"
Now examine how this parameter gets parsed:
A.	cmd.exe treats ^ as escape character and removes them. cmd.exe finds no double quoted parts because all " are escaped with ^	^"Bed Bath ^& \\\^"Beyond\^"^" ↓          ↓     ↓        ↓ ↓
B.	cmd.exe passes this as parameter to the C/C++ program	"Bed Bath & \\\"Beyond\""
C.	C/C++ program sees this as a double quoted parameter. Note that all " inside the parameter are escaped with \	┌───────────────────────┐  "Bed Bath & \\\"Beyond\""  ↓                       ↓
D.	C/C++ program applies the rule 2n+1 backslashes followed by a " produce n backslashes + a literal quotation mark \\\" becomes \" \" becomes "	Bed Bath & \\\"Beyond\"              ----      --
E.	Result is the desired parameter we started with	Bed Bath & \"Beyond"

Sample Test File:

• TestParams8_3.bat
  • 
    ShowParams.exe ^"Bed Bath ^& \\\^"Beyond\^"^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

Example 8.4:     (Bed) <Bath> & "Beyond" | \"Kohl^s		Parameter
Start with the parameter you want (parameter includes spaces)		(Bed) <Bath> & "Beyond" | \"Kohl^s
1.	Search for any " Double the number of \ immediately preceding any " Then add one more \ before each "	(Bed) <Bath> & \"Beyond\" | \\\"Kohl^s                  ↑       ↑    ↑↑↑
2.	Escape with ^ all special characters: ^ < > | & ( ) "
	i.e. replace  ^  with  ^^      replace  <  with  ^<      replace  >  with  ^>      replace  |  with  ^|      replace  &  with  ^&      replace  (  with  ^(      replace  )  with  ^)      replace  "  with  ^"	^(Bed^) ^<Bath^> ^& \^"Beyond\^" ^| \\\^"Kohl^^s   ↑    ↑  ↑     ↑  ↑   ↑        ↑  ↑     ↑     ↑
3.	double the number of trailing \	no trailing \
4.	Add a leading and trailing ^"	^"^(Bed^) ^<Bath^> ^& \^"Beyond\^" ^| \\\^"Kohl^^s^" ↑↑                                                ↑↑
5.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:		^"^(Bed^) ^<Bath^> ^& \^"Beyond\^" ^| \\\^"Kohl^^s^"
Now examine how this parameter gets parsed:
A.	cmd.exe treats ^ as escape character and removes them. cmd.exe finds no double quoted parts because all " are escaped with ^	^"^(Bed^) ^<Bath^> ^& \^"Beyond\^" ^| \\\^"Kohl^^s^" ↓ ↓    ↓  ↓     ↓  ↓   ↓        ↓  ↓     ↓     ↓  ↓
B.	cmd.exe passes this as parameter to the C/C++ program	"(Bed) <Bath> & \"Beyond\" | \\\"Kohl^s"
C.	C/C++ program sees this as a double quoted parameter. Note all " inside the double quoted parameter are escaped with \	┌──────────────────────────────────────┐   "(Bed) <Bath> & \"Beyond\" | \\\"Kohl^s"   ↓                                      ↓
D.	C/C++ program applies the rule 2n+1 backslashes followed by a " produce n backslashes + a literal quotation mark \" becomes " \\\" becomes \"	(Bed) <Bath> & \"Beyond\" | \\\"Kohl^s                   --      --   ----
E.	Result is the desired parameter we started with	(Bed) <Bath> & "Beyond" | \"Kohl^s

Sample Test File:

• TestParams8_4.bat
  • 
    ShowParams.exe ^"^(Bed^) ^<Bath^> ^& \^"Beyond\^" ^| \\\^"Kohl^^s^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

Example 8.5:     &<>^|()@!"		Parameter
Start with the parameter you want (parameter includes a space)		&<>^|()@!"
1.	Search for any " Double the number of \ immediately preceding any " Then add one more \ before each "	&<>^|()@!\"            ↑
2.	Escape with ^ all special characters: ^ < >| & ( ) "
	i.e. replace  ^  with  ^^      replace  <  with  ^<      replace  >  with  ^>      replace  |  with  ^|      replace  &  with  ^&      replace  (  with  ^(      replace  )  with  ^)      replace  "  with  ^"	^&^<^>^^^|^(^)^@^!\^"   ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑  ↑
3.	double the number of trailing \	no trailing \
4.	Add a leading and trailing ^"	^"^&^<^>^^^|^(^)^@^!\^"^" ↑↑                     ↑↑
5.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:		^"^&^<^>^^^|^(^)^@^!\^"^"
Now examine how this parameter gets parsed:
A.	cmd.exe treats ^ as escape character and removes them. cmd.exe finds no double quoted parts because all " are escaped with ^	^"^&^<^>^^^|^(^)^@^!\^"^" ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓  ↓ ↓
B.	cmd.exe passes this as parameter to the C/C++ program	"&<>^|()@!\""
C.	C/C++ program sees this as a double quoted parameter. Note all " inside the double quoted parameter are escaped with \	┌───────────┐  "&<>^|()@!\""  ↓           ↓
D.	C/C++ program applies the rule 2n+1 backslashes followed by a " produce n backslashes + a literal quotation mark \" becomes "	&<>^|()@!\"            --
E.	Result is the desired parameter we started with	&<>^|()@!"

Sample Test File:

• TestParams8_5.bat
  • 
    ShowParams.exe ^"^&^<^>^^^|^(^)^@^!\^"^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

The following older examples show the harder way of figuring out what to use as parameters.

(Note there are multiple ways of achieving the same result.)

Example 8.6: Command Line to C/C++ Program

Example 8.6a:     &<>^|()@ !			Parameter
Start with the parameter you want (parameter includes a space)			&<>^|()@ !
1.	Apply the Microsoft C/C++ parsing rules
	a.	replace: literal  "  with   \" literal \"  with  \\\" literal \\" with \\\\\"	nothing to replace
	b.	enclose the whole parameter in double quotes (because there's a space in the parameter)	┌──────────┐ "&<>^|()@ !" ↑          ↑
2.	Apply the Command Prompt parsing rules (cmd.exe)
	a.	determine what cmd.exe will see as the quoted parts	┌──────────┐ "&<>^|()@ !"
	b.	escape the special characters not in double quoted parts: ( the escape character for cmd.exe is ^ )	Nothing to escape because it's all in a double quoted part (as seen by cmd.exe)
	c.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:			"&<>^|()@ !"
Example 8.6b:     &<>^|()@ !			Parameter
Start with the parameter you want (same as example 1a)			&<>^|()@ !
1.	Apply the Microsoft C/C++ parsing rules
	a.	replace: literal  "  with   \" literal \"  with  \\\" literal \\" with \\\\\"	nothing to replace
	b.	enclose spaces in double quotes (A double quoted part can be anywhere within a parameter)	&<>^|()@" "!         ↑ ↑
2.	Apply the Command Prompt parsing rules (cmd.exe)
	a.	determine what cmd.exe will see as the quoted parts	┌─┐ &<>^|()@" "!
	b.	escape the special characters not in double quoted parts: ( the escape character for cmd.exe is ^ )	┌─┐ ^&^<^>^^^|^(^)^@" "^! ↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑    ↑
	c.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:			^&^<^>^^^|^(^)^@" "^!

Sample Test File:

• TestParams8_6.bat
  • REM both lines should produce the same result
    ShowParams.exe "&<>^|()@ !"
    ShowParams.exe ^&^<^>^^^|^(^)^@" "^!
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

Example 8.7: Command Line to C/C++ Program

Example 8.7:     &<>^|@()!"&<>^|@() !			Parameter
Start with the parameter you want			&<>^|@()!"&<>^|@()!
1.	Apply the Microsoft C/C++ parsing rules
	a.	replace: literal  "  with   \" literal \"  with  \\\" literal \\" with \\\\\"	&<>^|@()!\"&<>^|@()!          ↑
	b.	enclose the whole parameter in double quotes	"&<>^|@()!\"&<>^|@()!" ↑                    ↑
2.	Apply the Command Prompt parsing rules (cmd.exe)
	a.	determine what cmd.exe will see as the quoted parts	┌──────────┐         ┌─── "&<>^|()@!\"&<>^|@()!"
		we have a problem in that the final " is interpreted by cmd.exe as opening a double quoted part. To avoid this, escape that last " ( the escape character for cmd.exe is ^ )	┌──────────┐ "&<>^|()@!\"&<>^|@()!^"                      ↑
	b.	escape the other special characters not in double quoted parts: ( the escape character for cmd.exe is ^ )	┌──────────┐ "&<>^|@()!\"^&^<^>^^^|@()!^"             ↑ ↑ ↑ ↑ ↑
	c.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:			"&<>^|@()!\"^&^<^>^^^|@()!^"
Another way to get the same result would be at step 1b don't enclose the parameter in double quotes, then escape all special characters including the double quote so it doesn't start a double quoted part.			^&^<^>^^^|@()!\^"^&^<^>^^^|@()! ↑ ↑ ↑ ↑ ↑      ↑ ↑ ↑ ↑ ↑ ↑

Sample Test File:

• TestParams8_7.bat
  • REM both lines should produce the same result
    ShowParams.exe "&<>^|@()!\"^&^<^>^^^|@()!^"
    ShowParams.exe ^&^<^>^^^|@()!\^"^&^<^>^^^|@()!
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

Example 8.8: Command Line to C/C++ Program

Example 8.8a:     &<>^|@() !"&<>^|@() !			Parameter
Start with the parameter you want (parameter includes leading and trailing double quotes, plus a double quote inside, and two spaces)			"&<>^|@() !"&<>^|@() !"
1.	Apply the Microsoft C/C++ parsing rules
	a.	replace: literal  "  with   \" literal \"  with  \\\" literal \\" with \\\\\"	\"&<>^|@() !\"&<>^|@() !\" ↑           ↑           ↑
	b.	enclose the whole parameter in double quotes	┌──────────────────────────┐ "\"&<>^|@() !\"&<>^|@() !\"" ↑                          ↑
2.	Apply the Command Prompt parsing rules (cmd.exe)
	a.	determine what cmd.exe will see as the quoted parts	┌─┐           ┌───────────┐┌─── "\"&<>^|@() !\"&<>^|@() !\""
		we have a problem in that the final " is interpreted by cmd.exe as opening a double quoted part. To avoid this, escape that last " ( the escape character for cmd.exe is ^ )	┌─┐           ┌───────────┐ "\"&<>^|@() !\"&<>^|@() !\"^"                            ↑
	b.	escape the special characters not in double quoted parts: ( the escape character for cmd.exe is ^ )	┌─┐                ┌───────────┐ "\"^&^<^>^^^|@() !\"&<>^|@() !\"^"    ↑ ↑ ↑ ↑ ↑
	c.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:			"\"^&^<^>^^^|@() !\"&<>^|@() !\"^"
Another way to get the same result would be at step 2a just escape all special characters including all double quotes so there are no double quoted parts.			^"\^"^&^<^>^^^|@() !\^"^&^<^>^^^|@() !\^"^" ↑  ↑ ↑ ↑ ↑ ↑ ↑       ↑ ↑ ↑ ↑ ↑ ↑       ↑ ↑
Example 8.8b:     &<>^|@() !"&<>^|@() !			Parameter
Start with the parameter you want (same as 3a)			"&<>^|@() !"&<>^|@() !"
1.	Apply the Microsoft C/C++ parsing rules
	a.	replace: literal  "  with   \" literal \"  with  \\\" literal \\" with \\\\\"	\"&<>^|@() !\"&<>^|@() !\" ↑           ↑           ↑
	b.	enclose spaces in double quotes (A double quoted part can be anywhere within a parameter)	┌─┐           ┌─┐ \"&<>^|@()" "!\"&<>^|@()" "!\"           ↑ ↑           ↑ ↑
2.	Apply the Command Prompt parsing rules (cmd.exe)
	a.	determine what cmd.exe will see as the quoted parts	┌────────┐ ┌──┐        ┌─┐  ┌─── \"&<>^|@()" "!\"&<>^|@()" "!\"
		once again we have a problem in that the final " is interpreted by cmd.exe as opening a double quoted part. To avoid this, escape that last " ( the escape character for cmd.exe is ^ )	┌────────┐ ┌──┐        ┌─┐ \"&<>^|@()" "!\"&<>^|@()" "!\^"                              ↑
	b.	escape the other special characters not in double quoted parts: ( the escape character for cmd.exe is ^ )	┌────────┐ ┌──┐             ┌─┐ \"&<>^|@()" "!\"^&^<^>^^^|@()" "!\^"                 ↑ ↑ ↑ ↑ ↑
	c.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:			\"&<>^|@()" "!\"^&^<^>^^^|@()" "!\^"
Another way to get the same result would be at step 2a just escape all special characters including all double quotes so there are no double quoted parts.			\^"^&^<^>^^^|@()^" ^"!\^"^&^<^>^^^|@()^" ^"!\^"  ↑ ↑ ↑ ↑ ↑ ↑    ↑  ↑   ↑ ↑ ↑ ↑ ↑ ↑    ↑  ↑   ↑

Sample Test File:

• TestParams8_8.bat
  • REM all 4 lines should produce the same result
    ShowParams.exe "\"^&^<^>^^^|@() !\"&<>^|@() !\"^"
    ShowParams.exe ^"\^"^&^<^>^^^|@() !\^"^&^<^>^^^|@() !\^"^"
    ShowParams.exe \"&<>^|@()" "!\"^&^<^>^^^|@()" "!\^"
    ShowParams.exe \^"^&^<^>^^^|@()^" ^"!\^"^&^<^>^^^|@()^" ^"!\^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

Example 8.9: Command Line to C/C++ Program

Example 8.9a:     "C:\TEST A\"			Parameter
Start with the parameter you want (parameter includes double quotes and a space)			"C:\TEST A\"
1.	Apply the Microsoft C/C++ parsing rules
	a.	replace: literal  "  with   \" literal \"  with  \\\" literal \\" with \\\\\"	\"C:\TEST A\\\" ↑          ↑↑
	b.	enclose the whole parameter in double quotes (because there's a space in the parameter)	┌───────────────┐ "\"C:\TEST A\\\"" ↑               ↑
2.	Apply the Command Prompt parsing rules (cmd.exe)
	a.	determine what cmd.exe will see as the quoted parts	┌─┐            ┌┐ "\"C:\TEST A\\\""
	b.	escape the special characters not in double quoted parts: ( the escape character for cmd.exe is ^ )	No special characters to escape (as seen by cmd.exe)
	c.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:			"\"C:\TEST A\\\""
Another way to get the same result would be at step 2a just escape all special characters including all double quotes so there are no double quoted parts.			^"\^"C:\TEST A\\\^"^" ↑  ↑             ↑ ↑
Example 8.9b:     "C:\TEST A\"			Parameter
Start with the parameter you want (same as 4a)			"C:\TEST A\"
1.	Apply the Microsoft C/C++ parsing rules
	a.	replace: literal  "  with   \" literal \"  with  \\\" literal \\" with \\\\\"	\"C:\TEST A\\\" ↑          ↑↑
	b.	enclose spaces in double quotes (A double quoted part can be anywhere within a parameter)	\"C:\TEST" "A\\\"          ↑ ↑
2.	Apply the Command Prompt parsing rules (cmd.exe)
	a.	determine what cmd.exe will see as the quoted parts	┌───────┐ ┌────┐ \"C:\TEST" "A\\\"
	b.	escape the special characters not in double quoted parts: ( the escape character for cmd.exe is ^ )	It's all in double quoted parts. (as seen by cmd.exe)
	c.	if this will be placed in a batch file, double the % characters	no % in parameter
Result: To get desired parameter use this:			\"C:\TEST" "A\\\"
Another way to get the same result would be at step 2a just escape all special characters including all double quotes so there are no double quoted parts.			\^"C:\TEST^" ^"A\\\^"  ↑        ↑  ↑     ↑

Sample Test File:

• TestParams8_9.bat
  • REM all 4 lines should produce the same result
    ShowParams.exe "\"C:\TEST A\\\""
    ShowParams.exe ^"\^"C:\TEST A\\\^"^"
    ShowParams.exe \"C:\TEST" "A\\\"
    ShowParams.exe \^"C:\TEST^" ^"A\\\^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them.)

Example 8.10: Command Line to C/C++ Program

Example 8.10a:     "C:\TEST %&^ A\"			Parameter
Start with the parameter you want			"C:\TEST %&^ A\"
1.	Apply the Microsoft C/C++ parsing rules
	a.	replace: literal  "  with   \" literal \"  with  \\\" literal \\" with \\\\\"	\"C:\TEST %&^ A\\\" ↑              ↑↑
	b.	enclose the whole parameter in double quotes	┌───────────────────┐ "\"C:\TEST %&^ A\\\""
2.	Apply the Command Prompt parsing rules (cmd.exe)
	a.	determine what cmd.exe will see as the quoted parts	┌─┐                ┌┐ "\"C:\TEST %&^ A\\\""
	b.	escape the special characters not in double quoted parts: ( the escape character for cmd.exe is ^ )	┌─┐                   ┌┐ "\"C:\TEST ^%^&^^ A\\\""            ↑ ↑ ↑
	c.	if this will be placed in a batch file, double the % characters	┌─┐                    ┌┐ "\"C:\TEST ^%%^&^^ A\\\""             ↑
Result: To get desired parameter use this:			"\"C:\TEST ^%%^&^^ A\\\""
Another way to get the same result would be at step 2a just escape all special characters including all double quotes so there are no double quoted parts.			^"\^"C:\TEST %^&^^ A\\\^"^" ↑  ↑          ↑ ↑      ↑ ↑
	c.	and if this will be placed in a batch file, double the % characters	^"\^"C:\TEST %%^&^^ A\\\^"^"              ↑
Example 8.10b:     "C:\TEST %&^ A\"			Parameter
Start with the parameter you want (same as 5a)			"C:\TEST %&^ A\"
1.	Apply the Microsoft C/C++ parsing rules
	a.	replace: literal  "  with   \" literal \"  with  \\\" literal \\" with \\\\\"	\"C:\TEST %&^ A\\\" ↑              ↑↑
	b.	enclose spaces in double quotes (A double quoted part can be anywhere within a parameter)	┌─┐   ┌─┐ \"C:\TEST" "%&^" "A\\\"          ↑ ↑   ↑ ↑
2.	Apply the Command Prompt parsing rules (cmd.exe)
	a.	determine what cmd.exe will see as the quoted parts	┌───────┐ ┌───┐ ┌────┐ \"C:\TEST" "%&^" "A\\\"
	b.	escape the special characters not in double quoted parts: ( the escape character for cmd.exe is ^ )	it's all in double quoted parts (as seen by cmd.exe)
	c.	if this will be placed in a batch file, double the % characters	\"C:\TEST" "%%&^" "A\\\"             ↑
Result: To get desired parameter use this:			"\"C:\TEST ^%%^&^^ A\\\""
Another way to get the same result would be at step 2a just escape all special characters including all double quotes so there are no double quoted parts.			\^"C:\TEST^" ^"%^&^^^" ^"A\\\^"  ↑        ↑  ↑  ↑ ↑ ↑   ↑    ↑
	c.	and if this will be placed in a batch file, double the % characters	\^"C:\TEST^" ^"%%^&^^^" ^"A\\\^"                ↑

Sample Test File:

• TestParams8_10.bat
  • REM all 4 lines should produce the same result
    ShowParams.exe "\"C:\TEST ^%%^&^^ A\\\""
    ShowParams.exe ^"\^"C:\TEST %%^&^^ A\\\^"^"
    ShowParams.exe "\"C:\TEST ^%%^&^^ A\\\""
    ShowParams.exe \^"C:\TEST^" ^"%%^&^^^" ^"A\\\^"

---

9 How To Pass A Parameter to:
a Batch File from the Command Line

To get a parameter into a batch file you need to work backwards through the two parsings it will go through:

1. The cmd.exe command line parser parses your command line & parameters and then starts running the batch file
2. The batch file retrieves the parameters, but when you use them, they get parsed again. Here's an example:
   1. a batch file line contains %1
   2. %1 is replaced with your parameter
   3. that line is then sent to the command line parser for execution, where it gets parsed

Overview of steps:

1. Start with the parameter you want
2. Apply the command line parsing rules that cmd.exe will apply when you enter the command and parameters  [sec. 7]
3. Again, apply the command line parsing rules that cmd.exe will apply when you enter the command and parameters  [sec. 7]

Step Details:
The steps to create your parameter are:

1. Apply the Command Line Parser (cmd.exe) parsing rules
   1. determine what cmd.exe will see as the quoted parts
   2. escape the special characters < > | & ^ not in a double quoted part
   3. again, escape the special characters < > | & ^ not in a double quoted part
      • •the escape character for cmd.exe is ^
      • •it may also be necessary to escape ( ) @ !
      • •it's OK to escape everything
   4. If your command line will be placed in a batch file, double the % character⁷

The Command Line to Batch File Rules:

Combining the two steps above gives us the following rules:

• Use ^^^ outside double quotes to escape < > & | ^
     to insert < use ^^^<
     to insert > use ^^^>
     to insert | use ^^^|
     to insert ^ use ^^^^
• Sometimes it may be necessary to also escape ( ) @ !
• It's OK to escape everything
• Note ^ is also the line continuation character.

Space, Tab, Semicolon, Comma:
Note that you can't have a space within a parameter without having some double quotes around it somehow. All spaces must be within a double quoted part. Otherwise the space will act as a parameter delimiter. (Same with tabs, semicolons, commas.)

1. Command line arguments can be separated by an unquoted semicolon or comma. This affects builtin commands like COPY and batch file parameters.
2. If the command is called by name (no path), the following slash is treated a separator, as in DIR/P. This affects both builtin commands and external commands. Note: If you want to use NT-style slash-separated paths with DOS utilities you have to quote them (as in TYPE "C:/BOOT.INI").¹⁶

Example 9.1: Command Line to Batch File

Example 9.1:     &<>^|()@!			Parameter
Start with the parameter you want			&<>^|()@!
1.	Apply the Command Line to Batch File parsing rules
	a.	determine what cmd.exe will see as the quoted parts:	it's all unquoted
	b.	escape the special characters not in double quoted parts:	^^^&^^^<^^^>^^^^^^^|()@! ↑↑↑ ↑↑↑ ↑↑↑ ↑↑↑ ↑↑↑
Result: To get desired parameter use this:			^^^&^^^<^^^>^^^^^^^|()@!

Sample Test File:

• TestParams9_1.bat
  • ShowParams.bat ^^^&^^^<^^^>^^^^^^^|()@!
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them. WARNING! When executing a batch file from inside another batch file, the original batch file is terminated before the other one starts. This method of invoking a batch file from another is usually referred to as chaining.)

Example 9.2: Command Line to Batch File

Example 9.2:     &<>^|()@!			Parameter
Start with the parameter you want			┌─────────┐ "&<>^|()@!"
1.	Apply the Command Line to Batch File parsing rules
	a.	determine what cmd.exe will see as the quoted parts:	it's all in a double quoted part
	b.	escape the special characters not in double quoted parts:	Nothing to escape because it's all in a double quoted part (as seen by cmd.exe)
Result: To get desired parameter use this:			"&<>^|()@!"

Sample Test File:

• TestParams9_2.bat
  • ShowParams.bat "&<>^|()@!"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them. WARNING! When executing a batch file from inside another batch file, the original batch file is terminated before the other one starts. This method of invoking a batch file from another is usually referred to as chaining.)

Example 9.3: Command Line to Batch File

Example 9.3:     &<>^|()@!"&<>^|()@!			Parameter
Start with the parameter you want			&<>^|()@!"&<>^|()@!
1.	Apply the Command Line to Batch File parsing rules
	a.	determine what cmd.exe will see as the quoted parts:	┌─────────┐         ┌─── "&<>^|()@!"&<>^|()@!"
		we have a problem in that the final " is interpreted by cmd.exe as opening a double quoted part. To avoid this, escape that last "	┌─────────┐ "&<>^|()@!"&<>^|()@!^^^"                     ↑↑↑
	b.	escape the special characters not in double quoted parts:	┌─────────┐ "&<>^|()@!"^^^&^^^<^^^>^^^^^^^|()@!^^^"            ↑↑↑ ↑↑↑ ↑↑↑ ↑↑↑ ↑↑↑
Result: To get desired parameter use this:			"&<>^|()@!"^^^&^^^<^^^>^^^^^^^|()@!^^^"
Though not necessary, it's OK to escape the rest of the characters:			┌─────────┐ "&<>^|()@!"^^^&^^^<^^^>^^^^^^^|^^^(^^^)^^^@^^^!^^^"                                ↑↑↑ ↑↑↑ ↑↑↑ ↑↑↑
An easier way to get the same result would be to escape the " within the parameter so it doesn't end the double quoted part. Then nothing else needs to be escaped since it's all in a double quoted part.			┌────────────────────┐ "&<>^|()@!\"&<>^|()@!"           ↑
Another way to get the same result would be to escape all the special characters including all the " so nothing is in a double quoted part:
^^^"^^^&^^^<^^^>^^^^^^^|()@!^^^"^^^&^^^<^^^>^^^^^^^|()@!^^^"
As before, though it's not necessary, it is OK to escape the rest of the characters:
^^^"^^^&^^^<^^^>^^^^^^^|^^^(^^^)^^^@^^^!^^^"^^^&^^^<^^^>^^^^^^^|^^^(^^^)^^^@^^^!^^^"                         ↑↑↑ ↑↑↑ ↑↑↑ ↑↑↑                         ↑↑↑ ↑↑↑ ↑↑↑ ↑↑↑

Sample Test Files:
all 5 test files should produce the same result

• TestParams9_3a.bat
  • ShowParams.bat "&<>^|()@!"^^^&^^^<^^^>^^^^^^^|()@!^^^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them. WARNING! When executing a batch file from inside another batch file, the original batch file is terminated before the other one starts. This method of invoking a batch file from another is usually referred to as chaining.)

• TestParams9_3b.bat
  • ShowParams.bat "&<>^|()@!"^^^&^^^<^^^>^^^^^^^|^^^(^^^)^^^@^^^!^^^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them. WARNING! When executing a batch file from inside another batch file, the original batch file is terminated before the other one starts. This method of invoking a batch file from another is usually referred to as chaining.)

• TestParams9_3c.bat
  • ShowParams.bat "&<>^|()@!\"&<>^|()@!"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them. WARNING! When executing a batch file from inside another batch file, the original batch file is terminated before the other one starts. This method of invoking a batch file from another is usually referred to as chaining.)

• TestParams9_3d.bat
  • ShowParams.bat ^^^"^^^&^^^<^^^>^^^^^^^|()@!^^^"^^^&^^^<^^^>^^^^^^^|()@!^^^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them. WARNING! When executing a batch file from inside another batch file, the original batch file is terminated before the other one starts. This method of invoking a batch file from another is usually referred to as chaining.)

• TestParams9_3e.bat
  • ShowParams.bat ^^^"^^^&^^^<^^^>^^^^^^^|^^^(^^^)^^^@^^^!^^^"^^^&^^^<^^^>^^^^^^^|^^^(^^^)^^^@^^^!^^^"
    
    
    (Note: Since this is a batch file, if there were any % we would need to double them. WARNING! When executing a batch file from inside another batch file, the original batch file is terminated before the other one starts. This method of invoking a batch file from another is usually referred to as chaining.)

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10. How To Pass A Parameter to:
a VBScript, JScript, or WSH Script
from the Command Line

VBScript (.vbs), JScript⁹ (.js), and WSH (.wsh) scripts are run by program wscript.exe, which is the Microsoft® Windows® Script Host (WSH). WSH is a language-independent scripting host for Windows Script compatible scripting engines. Microsoft provides both Microsoft Visual Basic Script and JScript scripting engines with WSH. Windows Script Host executes scripts that exist outside an HTML or ASP page and that stand on their own as text files.¹⁰

     Example:
      > C:\WINDOWS\system32\wscript.exe ShowParams.vbs hello goodbye Friday

When you run ShowParams.vbs you'll notice the window title says, "Window Script Host".

“If you want to get picky, the truth is that you can’t read command-line arguments using VBScript; that’s because VBScript doesn’t know anything about command-line arguments. But that’s all right; after all, VBScript doesn’t have to know anything about command-line arguments. That’s because Windows Script Host takes care of all that stuff. “Any time you supply a command-line argument to a script that runs under Windows Script Host (that includes JScript scripts as well as VBScript scripts) those arguments are automatically stored in the Wscript.Arguments collection.”      —Hey, Scripting Guy! 2008 Winter Scripting Games: Retrieving Command-Line Arguments           http://www.microsoft.com/technet/scriptcenter/funzone/games/tips08/gtip0104.mspx

On startup wscript.exe calls GetCommandLine() to get the command line, then calls wscript!SplitCommandLine(), which parses off the parameters. The rules for WSH command line parameter parsing are simple:

10.1  The WSH Command Line Parameter Parsing Rules:

• parameters are separated by a space or tab (multiple spaces/tabs OK)
• " begins and ends the double quoted part)
• all characters within a double quoted part are accepted, including spaces and tabs)
• The " character itself is always stripped from the parameter)
  (Note this means you can not pass a double quote as part of a parameter.))

10.2  The Microsoft® Windows® Script Host (WSH) Command Line Parameter Parsing Algorithm:

The following algorithm was reverse engineered by disassembling and examining wscript.exe and cscript.exe:

Algorithm:

1. call Kernel32.dll!GetCommandLine() to get the command line
2. make a copy of the command line
3. call wscript!SplitCommandLine() dry run to determine the number of parameters
4. allocate space for argv[] array
5. call wscript!SplitCommandLine() to parse parameters and fill in argv[] array

wscript!SplitCommandLine() builds an argv[] array of where each parameter begins, and writes a terminating NULL at the end of each parameter.

Splitting the Command Line to get Parameters
start with: ShowParams.exe hello goodbye Friday end with:   ShowParams.exe0hello0goodbye0Friday0             ↑              ↑     ↑       ↑  argv[]     │              │     │       │ param 0: ───┘              │     │       │ param 1: ──────────────────┘     │       │ param 2: ────────────────────────┘       │ param 3: ────────────────────────────────┘

loop
   parse off next parameter:
   skip over spaces, tabs
   clear " flag
   save starting address of this parameter
   LOOP
      process this character:
      If space or tab
         if " flag set
            accept this space or tab as part of the parameter
         else
            write a 0 here to terminate this parameter
            and goto parse off next parameter
      Else if "
         toggle " flag, strip " (shift rest of line left 1 char)
      move to next char
   ENDLOOP
endloop

Notes:

• " flag - set if we're currently inside a double quoted part
• The algorithm only looks for {space}, {tab}, and ("). All other characters are just characters.
• You can't pass a double quote (") as part of a parameter because double quotes are always stripped off.

10.3  Putting it together:
When you launch a VBScript, JScript, or WSH script from the command line, your command line goes through two parsers:

1. First the cmd.exe command line parser parses your command & parameters, using its cmd.exe parsing rules. It builds a command line, and calls CreateProcess() passing it the command line it built.
2. Then the Windows Script Host retrieves that resulting command line and parses off the parameters, using its WSH parsing rules.

So to get a parameter into a VBScript, JScript, or WSH script, you need to work backwards through the two parsers it will go through:

1. Start with the parameter you want
2. Apply the WSH parsing rules that Windows Script Host will apply when parsing the command line it retrieves
3. Then apply the command line parsing rules that cmd.exe will apply when you enter the command and parameters

Step Details:
The steps to create your parameter are:

1. Apply the WSH parsing rules:
   1. if there are any spaces or tabs within a parameter, add some " so they are enclosed in a double quoted part
      •                                                         ┌───────────────┐
        •you may enclose the entire parameter in double quotes: "Call Me Ishmael"
      •                                                           ┌─┐  ┌─┐
        •or you may enclose just the spaces in double quotes: Call" "Me" "Ishmael
      •                                  ┌────────┐
        •or you can make a mess of it: Ca"ll Me Is"hmael
   
   
2. Apply the Command Line Parser (cmd.exe) parsing rules
   1. determine what cmd.exe will see as the double quoted parts
   2. escape the special characters < > | & ^ not in a double quoted part
      • •the escape character for cmd.exe is ^
      • •it may also be necessary to escape ( ) @ !
      • •it's OK to escape everything
   3. If your command line will be placed in a batch file, double the % character¹¹

10.4  Sample Scripts:

Sample 'Show Parameters' scripts:

VBScript:

• ShowParams.vbs
  • If Wscript.Arguments.Count = 0 Then
            Wscript.echo "No parameters found"
    Else
        i=0
            Do until i = Wscript.Arguments.Count
            Parms = Parms & "Param " & i & " = " & Wscript.Arguments(i) & " " & vbcr
            i = i+1
            loop
            Wscript.echo parms
    End If

JScript:

• ShowParams.js
  • if (WScript.Arguments.Count() ==0) {
      WScript.Echo("No parameters found");
    }
    else {
      var objArgs = WScript.Arguments;
      var parms = ""
      for (i=0, n=objArgs.length; i<n; i++) {
        parms += '\nParam '+i+'='+objArgs(i);
      }
      WScript.Echo(parms);
    }

---

11.How To Pass A Parameter to
a Perl script from the command line

ActivePerl¹² and Strawberry Perl¹³ both call MSVCRT.dll!__getmainargs which follows the Microsoft C/C++ Parameter Parsing Rules. Therefore the steps are:

1. Start with the parameter you want
2. Apply the Microsoft C/C++ parsing rules that ShowParams.exe will apply when parsing the command line it retrieves  [sec. 5]
3. Apply the command line parsing rules that cmd.exe will apply when you enter the command and parameters  [sec. 7]

See sec. 8: How To Pass A Parameter to: a C/C++ Program from the Command Line above.

Sample 'Show Parameters' Perl script:

• ShowParams.pl
  • if ( $#ARGV < 0 ) {
      print "No parameters\n";
    }
    else {
      my $i = 0;
      my $Parms = "";
      while ( $i <= $#ARGV ) {
        $Parms .= "Param $i = $ARGV[$i]\n";
        $i ++;
      }
      print $Parms;
    }

---

12.How To Pass A Parameter to
a Python script from the command line

Python™¹⁴ is written in C and obtains its parameters via the argv[] vector.¹⁵ It thus uses the Microsoft C/C++ Parameter Parsing Rules. Therefore the steps are:

1. Start with the parameter you want
2. Apply the Microsoft C/C++ parsing rules that ShowParams.exe will apply when parsing the command line it retrieves  [sec. 5]
3. Apply the command line parsing rules that cmd.exe will apply when you enter the command and parameters  [sec. 7]

See sec. 8: How To Pass A Parameter to: a C/C++ Program from the Command Line above.

Sample 'Show Parameters' Python script for Python version 2:

• ShowParams2.py
  • #!/usr/bin/python
    # Filename: using_sys.py
    import sys
    print 'The command line arguments are:'
    for i in sys.argv:
            print i
    print '\n\nThe PYTHONPATH is', sys.path, '\n'

Sample 'Show Parameters' Python script for Python version 3:

• ShowParams3.py
  • #!/usr/bin/python
    # Filename: using_sys.py
    import sys
    print( 'The command line arguments are:' )
    for i in sys.argv:
            print( i )
    print( '\n\nThe PYTHONPATH is', sys.path, '\n' )

Note: Python version 3 is incompatible with Python version 2. Guido van Rossum wrote "Python 3.0, also known as Python 3000 or Py3K, is the first ever intentionally backwards incompatible Python release." In particular, print statements that would work with pre-3 versions of Python will not work in 3.x. The change of "print" from a statement to a function is identified as a common stumbling block on this page on what's new in Python 3.0. http://docs.python.org/3.1/whatsnew/3.0.html

---

13.How To Pass A Parameter to
a REXX script from the command line

8/24/2009 Under Construction...

Sample 'Show Parameters' REXX script:

• ShowParams.rex
  • NumParams = %0%
    Param1 = %1%
    Param2 = %2%
    Param3 = %3%
    MsgBox GetCommandLine=%string%`nNumParams = %0%`nParam1 = %1%`nParam2 = %2%`nParam3 = %3%
    ExitApp

---

14.How To Pass A Parameter to
a RUBY script from the command line

Ruby attempts to mimic the Microsoft C/C++ parameter parsing rules, but the current versions, 1.8.6 & 1.9.1, have a bug in them so they don't work properly.

(file Win32.c routine rb_w32_cmdvector, the memcpy statement needs to copy one more character to include the trailing NULL.)

Sample 'Show Parameters' RUBY script:

• ShowParams.rb
  • ARGV.each do|a|
      puts "Argument: #{a}"
    end

---

15.How To Pass A Parameter to
an AutoHotkey script from the command line

AutoHotkey is written in C++ and obtains its parameters via the __argv[] vector. Thus it uses the Microsoft C/C++ Parameter Parsing Rules. Therefore the steps are:

1. Start with the parameter you want
2. Apply the Microsoft C/C++ parsing rules that ShowParams.exe will apply when parsing the command line it retrieves  [sec. 5]
3. Apply the command line parsing rules that cmd.exe will apply when you enter the command and parameters  [sec. 7]

See sec. 8: How To Pass A Parameter to: a C/C++ Program from the Command Line above.

Sample 'Show Parameters' AutoHotkey script:

• ShowParams.ahk
  • 
    NumParams = %0%
    Param1 = %1%
    Param2 = %2%
    Param3 = %3%
    result := DllCall("kernel32\GetCommandLineW")
    pointer := result
    string := DllCall("MulDiv","int",pointer,"int",1,"int",1,"str")
    MsgBox GetCommandLine=%string%`nNumParams = %0%`nParam1 = %1%`nParam2 = %2%`nParam3 = %3%
    ExitApp

---

Footnotes:

1.	Larry Osterman's WebLog The Windows command line is just a string... http://blogs.msdn.com/larryosterman/archive/2007/10/03/the-windows-command-line-is-just-a-string.aspx Thank you to Delan Azabani for the following explanation: Technically, execl(3) and friends do not allow you to specify a command line string [i], but rather a sequence of previously separated arguments via variadic C arguments. execv(3) and friends are similar, except that they use decayed arrays. The complete exec family includes exec{l,le,lp,v,ve,vp}, fexecve(3), and if you’re using glibc, the execvpe(3) extension. The family may be invoked in a way that allows you to specify a command line string — including, for example, together with sh(1): execl("/path/to/bin/sh", "sh", "-c", command_line, (char *) NULL); This is roughly how system(3) is specified by POSIX [ii]. [i] http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html [ii] http://pubs.opengroup.org/onlinepubs/9699919799/functions/system.html
2.	ibid.
3.	or possibly CScript.exe; WScript.exe is the Windows version, CScript.exe is the console version. You'll find them in the System32 directory.
4.	In some cases cmd.exe may call ShellExecute() which eventually calls CreateProcess(), passing it a command line.
5.	On Windows 95,98,ME the Command Prompt Window program was COMMAND.COM . The parsing rules are the same. (Back then it was also known as the DOS Prompt, or MS-DOS Prompt. Technically COMMAND.COM is DOS. Note there are other Command Prompt Window programs such as JPSoft's "Take Command". (http://jpsoft.com) Note the following CP/M legacy constructs: 1. Command line arguments can be separated by an unquoted semicolon or comma. This affects builtin commands like COPY and batch file parameters. In particular, I can think of no way to pass A;B (without quotes) as a paramater to a batch file. 2. If the command is called by name (no path), the following slash is treated a separator, as in DIR/P. This affects both builtin commands and external commands. Note: If you want to use NT-style slash-separated paths with DOS utilities you have to quote them (as in TYPE "C:/BOOT.INI").
6.	It's been documented in the past, such as here: "Percent Signs Stripped from Batch File Text" http://support.microsoft.com/kb/75634 and it's mentioned in current documentation here (last sentence of the "Copy Examples" section): "dtutil Utility" http://msdn.microsoft.com/en-us/library/ms162820.aspx Note: JPSoft's Take Command command line utility processes % differently. You'll need to quadruple the % char (http://jpsoft.com)
7.	See footnote 6
8.	See footnote 6
9.	JScript is Microsoft's own version of JavaScript.
10.	"Windows Script Host Basics" http://msdn.microsoft.com/en-us/library/ec0wcxh3(VS.85).aspx "Description of Windows Script Host (WSH)" http://support.microsoft.com/kb/188135 "Hosting Environments and Script Engines" http://msdn.microsoft.com/en-us/library/s4axe076(VS.85).aspx
11.	See footnote 6
12.	http://www.activestate.com/activeperl/
13.	http://strawberryperl.com/
14.	http://www.python.org/
15.	Technically, WinMain in WinMain.c calls Py_main in main.c passing it __argc and __wargv as argc[] and argv[] respectively.
16.	Thanks to Christopher Yeleighton for these two points.
17.	YoLinux.com: GNOME desktop basics → GNOME Desktop Launcher
18.	The KDE Menu Editor Handbook
19.	Thanks to András Korn for assistance in updating the *nix section (Feb. 2011).

---

David Deley © 2009
http://daviddeley.com

Updates:

July 5, 2020 — Thank you to Stefan Kanthak for pointing out some spelling errors.

Feb. 8, 2022 — Bash Cheat Sheet reference added.