Question

@echo off
set test=%1

if "%1"=="" (
set test=default
echo %test%
) else (
set test=%1
echo %test%
)

Test:

test.bat

Output:

ECHO is off

Problem: The ‘default’ string cannot be assigned as a value to variable ‘test’. I’ve found out that test string’s value is still %1 which has no value

Answer 1

It’s the standard batch beginner bug.
Percent expansion doesn’t work in parenthesis as you expected.
It expands when the complete block is parsed, before any of the lines are executed.

So %test% is expanded to nothing, the value before it enters the block.

The solution is to use delayed expansion here, as !test! will be expanded at execution not parse time.

@echo off
setlocal EnableDelayedExpansion
set test=%1

if "%1"=="" (
  set test=default
  echo !test!
) else (
  set test=%1
  echo !test!
)