[Discuss] How to keep '-' in bash args

[pw]

noel at natnix.com wrote:
> Ummm, what are you trying to do exactly?  There are simpler ways of
> breaking up args and pattern-matching than resorting to awk and sed:
> 
> args="1 2 3 -4 -5 -6"
> for arg in $args; do
>     case $arg in
>         -*) echo "opt: [$arg]" ;;
>         *) echo "noopt: [$arg]" ;;
>     esac
> done


I want to pass arguments to a shell script in the format:

script -flag1 value1 -flag2 value2 -flagn valuen

I want to be able to put the flags and accompanying values
in any order.

ie:

sh script.sh -flag7 value7 -flag3 value3 -flag1 value1

I want it to work just like a standard flagged command line
application without having to apply any special input
formatting to the arguments.

ie:

sh script.sh -flag1 value1 -flag2 value2 -flagn valuen

instead of:

sh script.sh  "-flag1 value1 -flag2 value2 -flagn valuen"

I finally rattled my head and remembered 'eval'. (duh!)


#!/bin/bash
#test4.sh

for ARG in `seq 1 256`; do
         eval C='$'$ARG;
         NEXT=`expr $ARG + 1`;
         eval D='$'$NEXT;
         L=`echo "$C" | wc -m |awk '{print $0-1}'`
         if [ "$L" -ne 0 ]; then
                 FLAG=`printf '%s\n' "$C" | sed -e "s/\ //g" | \
awk '{A=index($0,"-"); if(A==1){print "1" }else{ print "0"}}'`;
                 if [ "$FLAG" = "1" ]; then
                         echo "$C is a flag"
                         case "$C" in
                         "-flag1")
                         FLAG_ONE=$D
                         ;;
                         "-flag2")
                         FLAG_TWO=$D
                         ;;
                         ?)
                         ;;
                         esac
                 else
                         echo "$C is not a flag"
                 fi
         else
                 break
         fi
done

#PROGRAM USES ARGS HERE

echo "$FLAG_ONE $FLAG_TWO"

#END OF SCRIPT


run:

test4.sh -flag1 one -flag2 two

output:

-flag1 is a flag
one is not a flag
-flag2 is a flag
two is not a flag
one two


run:

test4.sh -flag2 two -flag1 one

output:

-flag2 is a flag
two is not a flag
-flag1 is a flag
one is not a flag
one two


Peter