Read environment variables from file in Windows Batch (cmd.exe)
Solution 1
You can do this in a batch file as follows:
setlocal
FOR /F "tokens=*" %%i in ('type Settings.txt') do SET %%i
java -Dsetting1=%setting1% ...
endlocal
This reads a text file containing strings like "SETTING1=VALUE1" and calls SET to set them as environment variables.
setlocal/endlocal are used to limit the scope of the environment variables to the execution of your batch file.
The CMD Command Processor is actually quite powerful, though with a rather byzantine syntax.
Solution 2
You can pass the property file as a parameter to a Java program (that may launch the main program later on). And then benefit from the multi platform paradigm.
Solution 3
It may be wise to only import specific variables from a properties file (ones you know about ahead of time), in that case I recommend a function like the following:
:parsePropertiesFile
set PROPS_FILE=%1
shift
:propLoop
if "%1"=="" goto:eof
FOR /F "tokens=*" %%i in ('type %PROPS_FILE% ^| findStr.exe "%1="') do SET %%i
shift
GOTO propLoop
goto:eof
Which would be called by call:parsePropertiesFile props.properties setting1 setting2
to set the variables setting1 and setting2
Martin Probst
Updated on December 24, 2021Comments
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Martin Probst over 2 years
I'm trying to read variables from a batch file for later use in the batch script, which is a Java launcher. I'd ideally like to have the same format for the settings file on all platforms (Unix, Windows), and also be a valid Java Properties file. That is, it should look like this:
setting1=Value1 setting2=Value2 ...
Is it possible to read such values like you would in a Unix shell script? The could should look something like this:
READ settingsfile.xy java -Dsetting1=%setting1% ...
I know that this is probably possible with
SET setting1=Value1
, but I'd really rather have the same file format for the settings on all platforms.To clarify: I need to do this in the command line/batch environment as I also need to set parameters that cannot be altered from within the JVM, like -Xmx or -classpath.
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Paolo Di Pietro over 15 yearsOh I see, it's sounds overkill compare to the solutions but you may re-launch the Java from another Java. Don't get my wrong I do prefer the selected solution.
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Pereira over 8 yearsAfter a long time looking for a solution, I found this solution. Thank you!
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malthe over 4 yearsHow would you ignore a "comment" (for example, a line starting with a "#" character) - ?
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Joe about 3 years@malthe - one way is just to ignore any error messages the comment lines produce, or hide them thus
FOR /F "tokens=*" %%i in ('type Settings.txt') do SET %%i 2> NUL:
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shurkam almost 3 years@malthe - Add eol=<comment character>.
FOR /F "tokens=* eol=#" %%i in ('type Settings.txt') do SET %%i
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Stephan over 2 yearsNo need for
/a
, as batch knows about only one variable type anyway: STRING.set /a
is used to translate strings into integers to do arithmetic and assigns again a string to the variable.