How do i ensure 2 arguments are passed in a bat file?
I would like to echo a description of the arguments and exit the bat if there are not exactly 2 arguments.
+2
A:
See Note 1 on this page about the need for a dummy when testing for empty strings.
IF dummy-==dummy-%1 (
ECHO Syntax is blah blah
EXIT /B
)
IF dummy-==dummy-%2 (
ECHO Syntax is blah blah
EXIT /B
)
Also I find this is a good reference when writing batch files.
harpo
2010-06-09 01:01:07
Per @Daniel's answer, I reckon the first check is redundant.
harpo
2010-06-09 01:07:10
I wrote IF dummy-==dummy-%2 ( ECHO Blah EXIT /B)IF NOT dummy-==dummy-%3 ( ECHO To many arguments EXIT /B)
acidzombie24
2010-06-09 01:19:02
That `dummy-` syntax is ugly and adds no value. CMD.EXE will compare the strings on either side of `==` character for character (after stripping leading and trailing whitespace), so you might as well say `if FOOBAR==FOO%1BAR` since it means the same thing. But my preference is to use quote characters since it's much more legible.
Daniel Pryden
2010-06-09 01:26:49
@Daniel, I agree your syntax looks better, but the quotes serve essentially the same purpose; that is, they add no semantic value but adjust for a syntactic consideration.
harpo
2010-06-09 02:32:16
+1
A:
Do
if "%2"=="" goto :usage
and then put your usage text at the bottom, after a :usage label. Just make sure you exit your script with goto :eof so you don't get the usage upon normal completion.
Daniel Pryden
2010-06-09 01:02:02
+1
A:
Here's another way using the for command:
@echo off
set /a argCount=0
for %%A in (%*) do set /a argCount+=1
@echo Number of args is: %argCount%
if %argCount% NEQ 2 (
@echo Usage
exit /b
)
This style will handle cases where you need to ensure you have more than 9 arguments.
Patrick Cuff
2010-06-09 11:29:01