Re: help with combining expressions in an if statement

[Chris F.A. Johnson]

On Sat, 1 Jan 2005, Jim wrote:

> Hi,
>
> I am new to bash and am looking for some help. Specifically, I would like to 
> ensure the user supplies two arguments to the shell script - month and year. 
> How should I combine multiple expressions in an if statement?
>
>
> So far I have the following script :
>
> month=$1
> year=$2
>
> if [ -z$month -o -z$year ]; then
> echo "Usage: $0 month year";
> echo "example: date.sh 01 2005";
> exit 1
> fi
>
> In other words I want to say if A is true OR B is true then echo output.

              The number of arguments is in the variable $#, so you can check
              that:

[ $# -ne 2 ] && {
            echo "Usage: $0 month year"
            echo "example: date.sh 01 2005"
}

              Or you can test each variable:

[ -n "$1" ] && [ -n "$2" ] || {
            echo "Usage: $0 month year"
            echo "example: date.sh 01 2005"
}


--
                Chris F.A. Johnson                      
http://cfaj.freeshell.org
                
=================================================================
                          Everything in moderation -- including moderation