Add usage content in shell script without getopts

Question

I have script where i need to display usage command in case user miss any mandatory information while executing script.

Usage : Script -s <server> -i <instance> -u <user> -p <password> <query> -w <warning value> -c <critical value>

With explanation about all the OPTIONS

I'm getting values from arguments as below variables fashion. But I want this usage with validations in shell script.

SERVER=$1
INSTANCE=$2
USER=$3
DB_PASSWD=$4
QUERY=$5
VAL_WARN=$6
VAL_CRIT=$7

I have tried using getopts, But failed to use since <query> doesn't have a -q parameter before passing the value.

I have tried finding all other ways, But everyone suggested getopts which is not feasible solution for me.

Please help me on this..

Answer 1

Use shift to iterate through all of your arguments, something like:

#!/bin/sh

usage ()
{
  echo 'Usage : Script -s <server> -i <instance> -u <user> -p <password>'
  echo '                  <query> -w <warning value> -c <critical value>'
  exit
}

if [ "$#" -ne 13 ]
then
  usage
fi

while [ "$1" != "" ]; do
case $1 in
        -s )           shift
                       SERVER=$1
                       ;;
        -i )           shift
                       INSTANCE=$1
                       ;;
        -u )           shift
                       USER=$1
                       ;;
        -p )           shift
                       PASSWORD=$1
                       ;;
        -w )           shift
                       WARNINGVAL=$1
                       ;;
        -c )           shift
                       CRITICVAL=$1
                       ;;
        * )            QUERY=$1
    esac
    shift
done

# extra validation suggested by @technosaurus
if [ "$SERVER" = "" ]
then
    usage
fi
if [ "$INSTANCE" = "" ]
then
    usage
fi
if [ "$USER" = "" ]
then
    usage
fi
if [ "$PASSWORD" = "" ]
then
    usage
fi
if [ "$QUERY" = "" ]
then
    usage
fi
if [ "$WARNINGVAL" = "" ]
then
    usage
fi
if [ "$CRITICVAL" = "" ]
then
    usage
fi

echo "ALL IS WELL. SERVER=$SERVER,INSTANCE=$INSTANCE,USER=$USER,PASSWORD=$PASSWORD,QUERY=$QUERY,WARNING=$WARNINGVAL,CRITIC=$CRITICVAL"

Should do the trick.

EDIT: added argument validation in the script as suggested by @technosaurus

Answer 2

getopts is bitching for a good reason. you should change your script's interface to conform to what people expect.

alternatively, you could use getopts twice, first for the pre-query options, shift, then for the rest.