Date: Tue, 14 Aug 2001 16:53:43 -0700 From: Drew Tomlinson <drewt@writeme.com> To: 'parv' <parv_@yahoo.com> Cc: "'FreeBSD Questions (E-mail)'" <freebsd-questions@FreeBSD.org> Subject: RE: Shell Script Help - Comparing Strings Message-ID: <5CD46247635BD511B6B100A0CC3F023925A06B@ldcmsx01.lc.ca.gov> In-Reply-To: <5CD46247635BD511B6B100A0CC3F0239E342B5@ldcmsx01.lc.ca.gov>
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> -----Original Message-----
> From: parv [mailto:parv_@yahoo.com]
> Sent: Tuesday, August 14, 2001 4:12 PM
> To: Drew Tomlinson
> Cc: FreeBSD Questions (E-mail)
> Subject: Re: Shell Script Help - Comparing Strings
>
>
> this was, on the fateful occasion around Aug 14 18:43 -0400,
> sent by Drew Tomlinson
> >
> > As I continue in writing my first shell script, I can't
> figure out how to
> > compare strings properly. For example, I want to run my
> script and pass an
> > argument to it from the command line. However, if this
> argument is not
> > passed, then I want to set it to a defined value. I'm
> trying to use the if
> > statement for this. Here's a clip of my code:
> >
> > #! /bin/sh -vx
> >
> > # 8/8/01
> > # An attempt to write script to run webalizer to generate
> web stats for all
> > # virtual web sites.
> >
> > # Set command line variables. $1 = web to run.
> >
> > # Set $1 to "www" if blank.
> > echo $1
> > if ["$1"=""]
> > then $1 = "www"
> > fi
> ...
>
> > echo $1
> > + echo test
> > test
> > if ["$1"=""]
> > then $1 = "www"
> > fi
> > + [test=]
> > [test=]: not found
> ...
>
> you need to add spaces between test operators...
>
> if [ "$1"="" ] # notice the difference
> then
> $1="www"
> fi
I see but this didn't work for me either. This is what I get.
if [ "$1"=="" ] #Tried with both single and double "="
then $1="www"
fi
+ [ test== ]
+ test=www
test=www: not found
Another poster explained that "=" sets a value but "==" should be used for
comparing strings. I tried it both ways but got the same error.
> ...but i would test the number of arguments, and set a non positional
> variable instead...
>
> case $# in
> 0)
> suffix=www
> ;;
>
> *)
> suffix=$1
> ;;
> esac
>
> ...but still better alternative, would be...
>
> suffix=${1:-www}
This is stuff I don't understand but thank you for sharing! I'm sure I'll
come across it when I get into this further. I've only had a intro unix
class so I only experienced the very basics.
Thanks,
Drew
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