Menu
Use double percent signs ( %% ) to carry out the for command within a batch file. Variables are case sensitive, and they must be represented with an alphabetical value such as %a, %b, or %c. ( <set> ) Required. Specifies one or more files, directories, or text strings, or a range of values on which to run the command.
When used in a command line, script, or batch file, %1 is used to represent a variable or matched string. For example, in a Microsoft batch file, %1 can print what is entered after the batch file name.
%0 is the name of the batch file. %~n0 Expands %0 to a file Name without file extension.
Delayed Expansion will cause variables within a batch file to be expanded at execution time rather than at parse time, this option is turned on with the SETLOCAL EnableDelayedExpansion command. Variable expansion means replacing a variable (e.g. %windir%) with its value C:\WINDOWS.
var2 is set, but the expansion in the line echo %var2% occurs before the block is executed.
At this time var2 is empty.
Therefore the delayedExpansion syntax exists, it uses ! instead of % and it is evaluated at execution time, not parse time.
Please note that in order to use !, the additional statement setlocal EnableDelayedExpansion is needed.
setlocal EnableDelayedExpansion
set var1=true
if "%var1%"=="true" (
set var2=myvalue
echo !var2!
)
I am a bit late to the party but another way to deal with this condition is to continue process outside if, like this
set var1=true
if "%var1%"=="true" (
set var2=myvalue
)
echo %var2%
Or/and use goto syntax
set var1=true
if "%var1%"=="true" (
set var2=myvalue
goto line10
) else (
goto line20
)
. . . . .
:line10
echo %var2%
. . . . .
:line20
This way expansion occurs "in time" and you don't need setlocal EnableDelayedExpansion. Bottom line, if you rethink design of your script you can do it like that
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With