Batch file include external file for variables

I have a batch file and I want to include an external file containing some variables (say configuration variables). Is it possible?

Note: I'm assuming Windows batch files as most people seem to be unaware that there are significant differences and just blindly call everything with grey text on black background DOS. Nevertheless, the first variant should work in DOS as well.

Executable configuration

The easiest way to do this is to just put the variables in a batch file themselves, each with its own set statement:

set var1=value1
set var2=value2
...

and in your main batch:

call config.cmd

Of course, that also enables variables to be created conditionally or depending on aspects of the system, so it's pretty versatile. However, arbitrary code can run there and if there is a syntax error, then your main batch will exit too. In the UNIX world this seems to be fairly common, especially for shells. And if you think about it, autoexec.bat is nothing else.

Key/value pairs

Another way would be some kind of var=value pairs in the configuration file:

var1=value1
var2=value2
...

You can then use the following snippet to load them:

for /f "delims=" %%x in (config.txt) do (set "%%x")

This utilizes a similar trick as before, namely just using set on each line. The quotes are there to escape things like <, >, &, |. However, they will themselves break when quotes are used in the input. Also you always need to be careful when further processing data in variables stored with such characters.

Generally, automatically escaping arbitrary input to cause no headaches or problems in batch files seems pretty impossible to me. At least I didn't find a way to do so yet. Of course, with the first solution you're pushing that responsibility to the one writing the config file.

If the external configuration file is also valid batch file, you can just use:

call externalconfig.bat

inside your script. Try creating following a.bat:

@echo off
call b.bat
echo %MYVAR%

and b.bat:

set MYVAR=test

Running a.bat should generate output:

test

Batch uses the less than and greater than brackets as input and output pipes.

>file.ext

Using only one output bracket like above will overwrite all the information in that file.

>>file.ext

Using the double right bracket will add the next line to the file.

(
echo
echo
)<file.ext

This will execute the parameters based on the lines of the file. In this case, we are using two lines that will be typed using "echo". The left bracket touching the right parenthesis bracket means that the information from that file will be piped into those lines.

I have compiled an example-only read/write file. Below is the file broken down into sections to explain what each part does.

@echo off
echo TEST R/W
set SRU=0

SRU can be anything in this example. We're actually setting it to prevent a crash if you press Enter too fast.

set /p SRU=Skip Save? (y): 
if %SRU%==y goto read
set input=1
set input2=2
set /p input=INPUT: 
set /p input2=INPUT2: 

Now, we need to write the variables to a file.

(echo %input%)> settings.cdb
(echo %input2%)>> settings.cdb
pause

I use .cdb as a short form for "Command Database". You can use any extension. The next section is to test the code from scratch. We don't want to use the set variables that were run at the beginning of the file, we actually want them to load FROM the settings.cdb we just wrote.

:read
(
set /p input=
set /p input2=
)<settings.cdb

So, we just piped the first two lines of information that you wrote at the beginning of the file (which you have the option to skip setting the lines to check to make sure it's working) to set the variables of input and input2.

echo %input%
echo %input2%
pause
if %input%==1 goto newecho
pause
exit

:newecho
echo If you can see this, good job!
pause
exit

This displays the information that was set while settings.cdb was piped into the parenthesis. As an extra good-job motivator, pressing enter and setting the default values which we set earlier as "1" will return a good job message. Using the bracket pipes goes both ways, and is much easier than setting the "FOR" stuff. :)

So you just have to do this right?:

@echo off
echo text shizzle
echo.
echo pause^>nul (press enter)
pause>nul

REM writing to file
(
echo XD
echo LOL
)>settings.cdb
cls

REM setting the variables out of the file
(
set /p input=
set /p input2=
)<settings.cdb
cls

REM echo'ing the variables
echo variables:
echo %input%
echo %input2%
pause>nul

if %input%==XD goto newecho
DEL settings.cdb
exit

:newecho
cls
echo If you can see this, good job!
DEL settings.cdb
pause>nul
exit

:: savevars.bat
:: Use $ to prefix any important variable to save it for future runs.

@ECHO OFF
SETLOCAL

REM Load variables
IF EXIST config.txt FOR /F "delims=" %%A IN (config.txt) DO SET "%%A"

REM Change variables
IF NOT DEFINED $RunCount (
    SET $RunCount=1
) ELSE SET /A $RunCount+=1

REM Display variables
SET $

REM Save variables
SET $>config.txt

ENDLOCAL
PAUSE
EXIT /B

Output:

$RunCount=1

$RunCount=2

$RunCount=3

The technique outlined above can also be used to share variables among multiple batch files.

Source: http://www.incodesystems.com/products/batchfi1.htm

Kinda old subject but I had same question a few days ago and I came up with another idea (maybe someone will still find it usefull)

For example you can make a config.bat with different subjects (family, size, color, animals) and apply them individually in any order anywhere you want in your batch scripts:

@echo off
rem Empty the variable to be ready for label config_all
set config_all_selected=

rem Go to the label with the parameter you selected
goto :config_%1

REM This next line is just to go to end of file 
REM in case that the parameter %1 is not set
goto :end

REM next label is to jump here and get all variables to be set
:config_all
set config_all_selected=1


:config_family
set mother=Mary
set father=John
set sister=Anna
rem This next line is to skip going to end if config_all label was selected as parameter
if not "%config_all_selected%"=="1" goto :end

:config_test
set "test_parameter_all=2nd set: The 'all' parameter WAS used before this echo"
if not "%config_all_selected%"=="1" goto :end

:config_size
set width=20
set height=40
if not "%config_all_selected%"=="1" goto :end


:config_color
set first_color=blue
set second_color=green
if not "%config_all_selected%"=="1" goto :end


:config_animals
set dog=Max
set cat=Miau
if not "%config_all_selected%"=="1" goto :end


:end

After that, you can use it anywhere by calling fully with 'call config.bat all' or calling only parts of it (see example bellow) The idea in here is that sometimes is more handy when you have the option not to call everything at once. Some variables maybe you don't want to be called yet so you can call them later.

Example test.bat

@echo off

rem This is added just to test the all parameter
set "test_parameter_all=1st set: The 'all' parameter was NOT used before this echo"

call config.bat size

echo My birthday present had a width of %width% and a height of %height%

call config.bat family
call config.bat animals

echo Yesterday %father% and %mother% surprised %sister% with a cat named %cat%
echo Her brother wanted the dog %dog%

rem This shows you if the 'all' parameter was or not used (just for testing)
echo %test_parameter_all%

call config.bat color

echo His lucky color is %first_color% even if %second_color% is also nice.

echo.
pause

Hope it helps the way others help me in here with their answers.

A short version of the above:

config.bat

@echo off
set config_all_selected=
goto :config_%1
goto :end

:config_all
set config_all_selected=1

:config_family
set mother=Mary
set father=John
set daughter=Anna
if not "%config_all_selected%"=="1" goto :end

:config_size
set width=20
set height=40
if not "%config_all_selected%"=="1" goto :end

:end

test.bat

@echo off

call config.bat size
echo My birthday present had a width of %width% and a height of %height%

call config.bat family
echo %father% and %mother% have a daughter named %daughter%

echo.
pause

Good day.

The best option according to me is to have key/value pairs file as it could be read from other scripting languages.

Other thing is I would prefer to have an option for comments in the values file - which can be easy achieved with eol option in for /f command.

Here's the example

values file:

;;;;;; file with example values ;;;;;;;;

;; Will be processed by a .bat file
;; ';' can be used for commenting a line

First_Value=value001

;;Do not let spaces arround the equal sign
;; As this makes the processing much easier
;; and reliable

Second_Value=%First_Value%_test

;;as call set will be used in reading script
;; refering another variables will be possible.

Third_Value=Something

;;; end

Reading script:

@echo off

:::::::::::::::::::::::::::::
set "VALUES_FILE=E:\scripts\example.values"
:::::::::::::::::::::::::::::

FOR /F "usebackq eol=; tokens=* delims=" %%# in (
	"%VALUES_FILE%"
) do (
	call set "%%#"
)

echo %First_Value% -- %Second_Value% -- %Third_Value%

While trying to use the method with excutable configuration I noticed that it may work or may NOT work depending on where in the script is located the call:

call config.cmd

I know it doesn't make any sens, but for me it's a fact. When "call config.cmd" is located at the top of the script, it works, but if further in the script it doesn't.

By doesn't work, I mean the variable are not set un the calling script.

Very very strange !!!!