CODEWITHSUNDEEP
batch-file
membersound
membersound

Reputation: 86627

How to check if a batch passed parameter exists?

How could I modify the following example code to check if the input parameter was given when starting the batch file?

Because the check IF NOT %MYDIR%==test fails and terminates the batch process if no paramter was provided.

SET MYDIR=%1

IF {no parameter given} OR NOT %MYDIR%==test (
   ECHO dir is not "test"
)

Upvotes: 0

Views: 2798

Answers (2)

dbenham
dbenham

Reputation: 130809

It is surprisingly difficult to handle all possibilities when dealing with passed parameters. But the following strategy works under most "ordinary" situations.

if "%~1" equ "" echo arg 1 was not passed

It is important that the ~ modifier is used because you have no way of knowing if the passed argument is already enclosed in quotes. If an argument like "this&that" is passed and you don't first remove the quotes before adding your own, then you get if ""this&that"" equ "". The & is no longer quoted and your command no longer parses properly.

Upvotes: 6

Alex
Alex

Reputation: 23300

Strings cannot be completely empty, a common way to work around this constraint is to enclose strings in quotes like this

... OR NOT "%MYDIR%"=="test"

or you can add something meaningless without enclosing the string (ugly!)

... OR NOT XXX%MYDIR%==XXXtest

Upvotes: 0

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