Setting variables inside IF/ELSE statement in Windows CMD batch file

Question

I've simple cmd script:

@echo off
if  %1.==. (
    echo Missing argument
) else (
    SET somevar=%1
    echo %1
    echo %somevar%
)

Problem with that is it looks like echo of variable somevar in else block are running before variable is set. Every time I run this, echo of argument working well but echo of variable shows value from previous run. This is happening only in if/else block and I don't understand why. If I modify script like that:

@echo off
if  %1.==. (
    echo Missing argument
    exit /B
)

SET somevar=%1
echo %1
echo %somevar%

result is as I expected. Running the script alternately with different argument gives clear view of an issue.

I've read some posts eg. How to clear variables after each batch script run? but I think it's different kind of problem.

So, is there any way to protect against such behavior inside IF/ELSE statement?

You should ideally change `if %1.==. (` to `If "%~1" == "" (` too. — Compo, Jun 14 '19 at 14:23

score 3 · Accepted Answer · answered Jun 14 '19 at 13:35

@echo off
if  %1.==. (
    echo Missing argument
) else (
    SET somevar=%1
    echo %1
    CALL echo %%somevar%%
)

or

@echo off
SETLOCAL EnableDelayedExpansion
if  %1.==. (
    echo Missing argument
) else (
    SET somevar=%1
    echo %1
    echo !somevar!
)

Resources (required reading):

(command reference) An A-Z Index of the Windows CMD command line
(additional particularities) Windows CMD Shell Command Line Syntax
(special page) EnableDelayedExpansion
(CALL echo %%somevar%%) (note doubled percent signs)
(it's not %1% but %1) Command Line arguments (Parameters)

Setting variables inside IF/ELSE statement in Windows CMD batch file

1 Answers1