Shell Programming and Scripting

#!/bin/ksh

input='[alskhdf]'

case $input in

  \[*\]) echo good ;;
  *) echo bad ;;

esac

> invalue="[John,Dan,]"
> if [ `echo "${invalue}" | tr "[:alpha:]" "~" | tr -s "~"` != "[~,~]" ] ; then echo "Bad input format; should be [name1,name2]"; fi
Bad input format; should be [name1,name2]

> invalue="[John,Dan]"
> if [ `echo "${invalue}" | tr "[:alpha:]" "~" | tr -s "~"` != "[~,~]" ] ; then echo "Bad input format; should be [name1,name2]"; fi
>

eval input=$@
VALID="false"
while [ "$VALID" != "true" ]
do
    echo $input |awk '/^\[/ {print}'
    if [ $? -eq 0 ]
    then
        echo $input |awk '/\]$/ {print}'
        if [ $? -eq 0 ]
        then
            echo "good"
            VALID="true"
        else
            echo "Please enter the input ending with ]"
            VALID="false"
        fi
    else
        echo "Please enter the input starting with ["
        VALID="false"
    fi
done