2212msr@whuts.UUCP (ROBIN) (02/11/86)
Does anyone know how to detect a null as variable input in a batch file?
Specifically:
foo %1 --how do I detect case where %1 is omitted, thus avoiding
an error? I've tried:
if %1==''
if %1==' '
if %1==<CTRL @>
all to no avail. Any help or pointers would be appreciated.
Max S. Robin
AT&T Bell Laboratories
201-386-6865
email:whuxg!2212msrlotto@talcott.UUCP (Jerry Lotto) (02/11/86)
In article <534@whuts.UUCP>, 2212msr@whuts.UUCP (ROBIN) writes: > Does anyone know how to detect a null as variable input in a batch file? The simplest solution is: if %1.==. goto null ... process :null echo No input on command line -- Gerald Lotto - Harvard Chemistry Dept. UUCP: {seismo,harpo,ihnp4,linus,allegra,ut-sally}!harvard!lhasa!lotto ARPA: lotto@harvard.EDU CSNET: lotto%harvard@csnet-relay
lotto@talcott.UUCP (Jerry Lotto) (02/11/86)
In article <534@whuts.UUCP>, 2212msr@whuts.UUCP (ROBIN) writes: > Does anyone know how to detect a null as variable input in a batch file? **** > Specifically: > > foo %1 --how do I detect case where %1 is omitted, thus avoiding ******** What do you really want to do here? If you want to detect no args, see the previous posting. If you want to pass a null (ascii 0) on a command line past the command processor, forget it. The command line parser will not respect your wishes. -- Gerald Lotto - Harvard Chemistry Dept. UUCP: {seismo,harpo,ihnp4,linus,allegra,ut-sally}!harvard!lhasa!lotto ARPA: lotto@harvard.EDU CSNET: lotto%harvard@csnet-relay
tang@Shasta.ARPA (02/12/86)
> foo %1 --how do I detect case where %1 is omitted, thus avoiding > an error? I've tried: > if %1=='' > if %1==' ' > if %1==<CTRL @> > all to no avail. Any help or pointers would be appreciated. Try this, I guess it will work :-) if $%1$ == $$ ----------------------------------- -mkt
story@calma.UUCP (Glen Story) (02/12/86)
In article <533@whuts.UUCP> 2212msr@whuts.UUCP (ROBIN) writes: >Does anyone know how to detect a null as variable input in a batch file? >Specifically: > >foo %1 --how do I detect case where %1 is omitted, thus avoiding > an error? I've tried 'if %1=='':goto xx' as well as >==' ' The following will solve your problem: if x%1 == x goto ...
kim@mips.UUCP (Kim DeVaughn) (02/12/86)
[ ... go ahead, eat my bits ... ] > Does anyone know how to detect a null as variable input in a batch file? > Specifically: > > foo %1 --how do I detect case where %1 is omitted, thus avoiding > an error? I've tried 'if %1=='':goto xx' as well as > ==' ' Hmmm ... I should probably try this out first, but my MS-DOS machine is unavailable right now. I *think* this will do what you want: if .%1 == . goto xx Note the "dots". Also, I pretty sure that this will work too: if "%1" == "" goto xx /kim -- UUCP: {decvax,ucbvax,ihnp4}!decwrl!mips!kim DDD: 415-960-1200 USPS: MIPS Computer Systems Inc, 1330 Charleston Rd, Mt View, CA 94043
pwong@pixel.DEC (Paul H. Wong, DPS/Graphics, 264-7918) (02/12/86)
<Max S. Robin writes:> >foo %1 --how do I detect case where %1 is omitted, thus avoiding > an error? I've tried: > if %1=='' > if %1==' ' > if %1==<CTRL @> > all to no avail. Any help or pointers would be appreciated. This seems to work for me: if Z%1==Z - Paul --------------------------------------------------------------------- Paul H. Wong Digital Equipment Corp. Merrimack, NH (603)-884-7918 ARPA: PWong%PIXEL.DEC@decwrl.arpa USENET: {allegra|decvax|ihnp4|ucbvax}!decwrl!dec-rhea!dec-pixel!pwong
boykin@datagen.UUCP (02/15/86)
<Max S. Robin writes:> >foo %1 --how do I detect case where %1 is omitted, thus avoiding > an error? I've tried: > if %1=='' > if %1==' ' > if %1==<CTRL @> > all to no avail. Any help or pointers would be appreciated. I use the following to test for a null (non-existent) argument: IF '%1' == '' Joe Boykin Sr. Project Leader Data General Corp. {allegra, ihnp4, decvax}!datagen!boykin
ogasawar@noscvax.UUCP (Todd H. Ogasawara) (02/21/86)
In article <22@datagen.UUCP> boykin@datagen.UUCP writes: ><Max S. Robin writes:> >>foo %1 --how do I detect case where %1 is omitted, thus avoiding >> an error? I've tried: This works pretty good for me: IF %0%1==%0 GOTO ... %0 always equals itself if there is no arg following the invocation of the batch command name itself. Todd Ogasawara, Computer Sciences Corp. NOSC-Hawaii Laboratories UUCPmail: {akgua,allegra,decvax,ihnp4,ucbvax}!sdcsvax!noscvax!ogasawar MILNET: OGASAWAR@NOSC