Posted By: Anonymous
I need to test if a variable is set or not. I’ve tried several techniques but they seem to fail whenever
%1 is surrounded by quotes such as the case when
"c:some path with spaces".
IF NOT %1 GOTO MyLabel // This is invalid syntax IF "%1" == "" GOTO MyLabel // Works unless %1 has double quotes which fatally kills bat execution IF %1 == GOTO MyLabel // Gives an unexpected GOTO error.
According to this site, these are the supported
IF syntax types. So, I don’t see a way to do it.
IF [NOT] ERRORLEVEL number command IF [NOT] string1==string2 command IF [NOT] EXIST filename command
UPDATE: on 2020-10-25, I updated the accepted answer from using brackets to using a tilde. Everyone says the tilde is better as it’s more secure. I’m a little torn cause the tilde looks more complicated and is less clear as to what it’s purpose is but nevertheless, I changed it.
You can use:
IF "%~1" == "" GOTO MyLabel
to strip the outer set of quotes. In general, this is a more reliable method than using square brackets because it will work even if the variable has spaces in it.