CODEWITHSUNDEEP
batch-file
James
James

Reputation: 123

batch files calling %~1 and getting the variable's current value/string

The code below is related to batch files (command prompt). My problem is the part of the code that says current value is %~1 doesn't actually display the value of %~1 (I would like it to say string01 or string02) am not too sure how to do this. I have looked around but cannot wrap my head around this simple problem.

@echo off 
goto :MainFunction 

:Func01 
echo. 
echo Running Func01 
echo Variable %~1 current value is %~1 
echo. 
echo Set new value for Variable %~1: 
set /p %~1= 
goto :eof 

:MainFunction 
echo This is the main function! 
set Var01=string01 
set var02=string02 
echo Var01 is equal to %Var01% 
echo Var02 is equal to %Var02% 
call :Func01 Var01 
call :Func01 Var02 
echo Var01 is now equal to %Var01% 
echo Var02 is now equal to %Var02% 
goto :eof

Upvotes: 3

Views: 655

Answers (2)

Mofi
Mofi

Reputation: 49127

Another method is using command CALL to get a double parsing of a command line as shown below:

@echo off
goto :MainFunction

:Func01
echo/
echo Running Func01
call echo Variable %~1 current value is %%%~1%%
echo/
set /P "%~1=Set new value for Variable %~1: "
goto :EOF

:MainFunction
echo This is the main function!
set "Var01=string01"
set "var02=string02"
echo Var01 is equal to %Var01%
echo Var02 is equal to %Var02%
call :Func01 Var01
call :Func01 Var02
echo Var01 is now equal to %Var01%
echo Var02 is now equal to %Var02%
goto :EOF

The command line

call echo Variable %~1 current value is %%%~1%%

is first modified before running CALL by Windows command interpreter for example on first execution of subroutine Func01 to

call echo Variable Var01 current value is %Var01%

On parsing this command line a second time on running CALL the command line changes to:

echo Variable Var01 current value is string01

The character % must be escaped with one more % to be interpreted as literal character in a batch file which is the reason for the strange looking syntax %%%~1%%.

And take a look on DosTips forum topic ECHO. FAILS to give text or blank line - Instead use ECHO/ for the explanation on using echo/ instead of echo. to output an empty line.

Upvotes: 2

Stephan
Stephan

Reputation: 56188

You want to get both the variable name and the value in a single parameter?

In the line echo Variable %~1 current value is %~1 , the second %~1 has to evaluated. Sou need another layer of parsing. The "usual" way to do so, is to use delayed expansion:

@echo off 
setlocal enabledelayedexpansion
goto :MainFunction 

:Func01 
echo. 
echo Running Func01 
echo Variable %~1 current value is !%~1! 
echo. 
echo Set new value for Variable %~1: 
set /p %~1= 
goto :eof 

:MainFunction 
echo This is the main function! 
set Var01=string01 
set var02=string02 
echo Var01 is equal to %Var01% 
echo Var02 is equal to %Var02% 
call :Func01 Var01 
call :Func01 Var02 
echo Var01 is now equal to %Var01% 
echo Var02 is now equal to %Var02% 
goto :eof

Upvotes: 3

Related Questions