if statement

sam srf10130 at vtc.vsc.edu
Thu Aug 20 16:48:34 UTC 2009


Ray Parrish wrote:
> Hello,
> 
> I am having difficulty with an if statement. Here it is -
> 
> # load the sleep interval in seconds from the command line.
> interval=$2;
>     # if specified interval in seconds is less than 200 or empty, set it 
> to the default of 300 seconds
>     if  [ $interval == "" ]
> 
>         then
>             interval=300; # five minutes default setting
>             echo "interval blank";
>     fi
> 
> Here is the error I keep getting, no matter how I try to change the if 
> statement around -
> 
> ray at RaysComputer:~$ ~/WebChange/UpdateWebURL.sh 
> http://finance.yahoo.com/q?s=MSFT
> /home/ray/WebChange/UpdateWebURL.sh: line 25: [: ==: unary operator expected
> 
> I actually want to check to see if interval is blank or less than 200, 
> but I can't seem to get that to work.
> 
> This happens with a single "=" as well. What am I doing wrong here?
> 
> Thanks for any help you can be. Later, Ray Parrish
> 
the use of square brackets (if [...]) uses linux command test to provide
the boolean value.

try man test for starters

sam




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