<tt>if</tt> statement


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if statement

What would happen if no parameters had been passed to the script Here is how one can verify that there is at least one parameter in the list: 

    #!/bin/sh
    if test $# -eq 0
    then
        echo there must be at least one parameter on the command line
    else
        until test $# -eq 0
        do
            echo parameter $1
            shift
        done
    fi
    exit 0
Another way to write this same program is 
    #!/bin/sh
    if test $# -eq 0
    then
        echo there must be at least one parameter on the command line
        exit 1
    fi
    until test $# -eq 0
    do
        echo parameter $1
        shift
    done
    exit 0
Note that the format of the if statement is
if comparison
then
. . .
else
. . .
fi
The else is optional, or if followed by another if, could be replaced by elif. The statement is ended by fi (``if" spelled backwards).


Super-User
Fri Feb 17 15:55:40 EST 1995