string comparison in batch file

Question

How do we compare strings which got space and special chars in batch file?

I am trying:

if %DevEnvDir% == "C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\"(
echo VS2010
)

But it gives an error "Files was unexpected at this time."

I tried:

if "%DevEnvDir%" == "C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\"(
echo VS2010
)

But it gives an error "The syntax of the command is incorrect."

Any ideas?

Answer 1

Just put quotes around the Environment variable (as you have already done):

if "%DevEnvDir%" == "C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\"

The strings you are comparing are fine, the problem is the way you put the opening bracket without a space. That is confusing it.

Works for me...

C:\if "%gtk_basepath%" == "C:\Program Files\GtkSharp\2.12\" (echo yes)
yes

Answer 2

While @ajv-jsy's answer works most of the time, I had the same problem as @MarioVilas. If one of the strings to be compared contains a double quote ("), the variable expansion throws an error.

Example:

@echo off
SetLocal

set Lhs="
set Rhs="

if "%Lhs%" == "%Rhs%" echo Equal

Error:

echo was unexpected at this time.

---

Solution:

Enable delayed expansion and use ! instead of %.

@echo off
SetLocal EnableDelayedExpansion

set Lhs="
set Rhs="

if !Lhs! == !Rhs! echo Equal

:: Surrounding with double quotes also works but appears (is?) unnecessary.
if "!Lhs!" == "!Rhs!" echo Equal

---

I have not been able to break it so far using this technique. It works with empty strings and all the symbols I threw at it.

Test:

@echo off
SetLocal EnableDelayedExpansion

:: Test empty string
set Lhs=
set Rhs=
echo Lhs: !Lhs! & echo Rhs: !Rhs!
if !Lhs! == !Rhs! (echo Equal) else (echo Not Equal)
echo.

:: Test symbols
set Lhs= \ / : * ? " ' < > | %% ^^ ` ~ @ # $ [ ] & ( ) + - _ =
set Rhs= \ / : * ? " ' < > | %% ^^ ` ~ @ # $ [ ] & ( ) + - _ =
echo Lhs: !Lhs! & echo Rhs: !Rhs!
if !Lhs! == !Rhs! (echo Equal) else (echo Not Equal)
echo.

Answer 3

A roundabout solution use a subroutine

CALL :Comparator %var1% %var2% <- or the string you want to compare
IF %retVal%==1 (
   do stuff
) ELSE (
   do other things
)

GOTO :eof

:Comparator
  IF "%~1" == "%~2" (set retVal=1) ELSE (set retVal=0)
GOTO :eof

It won't work if there is double-quotes inside the strings though, but if you compare file paths, there shouldn't be. %~[1-9] the tilde '~' removes double quotes around the variable, and then you put new ones around them if the strings has spaces inside. The tilde trick only works with passed variable though, hence the subroutine.

Answer 4

The solution is DO NOT USE SPACES!

IF "%DevEnvDir%"=="C:\" (