Shell Programming and Scripting

$ string1="123456789 abc2"
$ string2="abc"
$ position_of_string2=`expr index "$string1" "$string2"`
$ echo $position_of_string2
$
11

$ string1="123456789 abc2"
$ string2="abc2"
$ position_of_string2=`expr index "$string1" "$string2"`
$ echo $position_of_string2
$
2

       index STRING CHARS
              index in STRING where any CHARS is found, or 0

# Strip everything up to and including string2 from front of string1
string3="${string1##*${string2}}"

if [ "${#string3}" -eq "${#string1}" ]
then
        echo "${string2} not found in ${string1}"
else
        # Remaining length of string3 is length of string1 - (offset+length of string2)
        echo "offset is $(( 1+(${#string1}-${#string3})-${#string2}))"
fi

$ string1="123456789 abc2"

$ echo $string1
123456789 abc2

$ echo $string1 | awk -v v1="abc2" '{print $0,"___",v1,"___",index($0,v1)}'
123456789 abc2 ___ abc2 ___ 11

string3="${string1##*${string2}}"