Comparing Strings

String comparisons are done using $=$ and !$=$:

    #!/bin/sh
    if test $# -eq 0
    then
        echo Must provide parameters.
        exit 1
    fi
    
    while test ! $1 = "end"
    do
        echo parameter is $1
        shift
        if test $# -eq 0
        then
            echo Parameter list MUST contain the '"'end'"' string.
            exit
        fi
    done
    echo Done: I"'"ve hit the '"'end'"' string.
    exit 0

Note that the above example could have been MUCH shorter if no error checking took place.

The length of strings can also be tested using:

-z

: check if the string has zero length.

-n

: check if the string has a non-zero length.