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Home > Archive > Unix Shell > March 2005 > bash : what is wrong of this if command
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bash : what is wrong of this if command
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| clinton__bill@hotmail.com 2005-03-30, 7:55 am |
| Hi,
I just come to bash from csh, there is one problem in using if
command:
bash-2.05b$ if [ `uname`=="SunOS" ]; then echo haha; fi
haha
bash-2.05b$ if [ `uname`!="SunOS" ]; then echo haha; fi
haha
Do you see the problem of the above 2 if command. If I run "uname", I
see "Linux" returns.
Thanks.
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| Andre Majorel 2005-03-30, 7:55 am |
| On 2005-03-25, Chris F.A. Johnson <cfajohnson@gmail.com> wrote:
> On Fri, 25 Mar 2005 at 17:08 GMT, clinton__bill@hotmail.com wrote:
>
> You need spaces around the operator:
>
> if [ "`uname`" = "SunOS" ]; then echo haha; fi
>
> if [ "`uname`" != "SunOS" ]; then echo haha; fi
And, as Chris did, use "=" for equality. "==" is not portable.
--
André Majorel <URL:http://www.teaser.fr/~amajorel/>
(Counterfeit: qipiriquh@gasohol.com zydeheh@dissuade.com)
What worries me is not the violence of the few, but the
indifference of the many. -- M. L. King
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| William Park 2005-03-30, 7:55 am |
| clinton__bill@hotmail.com wrote:
> Hi,
> I just come to bash from csh, there is one problem in using if
> command:
>
> bash-2.05b$ if [ `uname`=="SunOS" ]; then echo haha; fi
> haha
> bash-2.05b$ if [ `uname`!="SunOS" ]; then echo haha; fi
> haha
>
> Do you see the problem of the above 2 if command. If I run "uname", I
> see "Linux" returns.
You need space around '=' and '!=', like
if [ `uname` = "SunOS" ]; ...
if [ `uname` != "SunOS" ]; ...
--
William Park <opengeometry@yahoo.ca>, Toronto, Canada
Slackware Linux -- because it works.
| |
| Chris F.A. Johnson 2005-03-30, 8:47 pm |
| On Fri, 25 Mar 2005 at 17:08 GMT, clinton__bill@hotmail.com wrote:
> Hi,
> I just come to bash from csh, there is one problem in using if
> command:
>
> bash-2.05b$ if [ `uname`=="SunOS" ]; then echo haha; fi
> haha
> bash-2.05b$ if [ `uname`!="SunOS" ]; then echo haha; fi
> haha
>
> Do you see the problem of the above 2 if command. If I run "uname", I
> see "Linux" returns.
You need spaces around the operator:
if [ "`uname`" = "SunOS" ]; then echo haha; fi
if [ "`uname`" != "SunOS" ]; then echo haha; fi
--
Chris F.A. Johnson http://cfaj.freeshell.org/shell
========================================
===========================
My code (if any) in this post is copyright 2005, Chris F.A. Johnson
and may be copied under the terms of the GNU General Public License
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