Comparing two strings in Bash

Replace -eq with == so your if block would be this:-

if [ ${PACKAGENAME} == kakadu-v6_4-00902C ]; then

        echo "successfully entered if block!!"

fi

Another way is to negate them:

: ${PACKAGENAME:?'$PACKAGENAME variable is empty!'} #emits error and exits
[ -z "${PACKAGENAME#kakadu-v6_4-00902C}" ] || { #if var - str not empty do block
    echo '$PACKAGENAME is not kakadu-v6_4-00902C' 
    exit 1
} >&2

The above block first tests if "$PACKAGENAME" has any value at all, and, if not it exits with error and echoes ?'this'} to stderr. If its parent shell still exists then the test has passed, and it next tests if removing your 'kakadu...' string from the variable results in an -z empty string. If it does not, then it again emits an error and exits the shell. If your shell still exists at this point anything after the block is executed, otherwise it is not.

Probably this sort of thing is best implemented in a function. Like:

argeq() ( unset ERR
    : ${2-${ERR?not enough parameters!}} #quit w/ err if not at least 2 args
    z() { return $((${#1}>0)) ; } #return 1 if 1st arg's len > 0 else 0
    until z "${2+?}" #until $2 is not set...
    do  ! z "$1" && z "${1#"$2"}" || exit #$1 != '' && $1 - $2 == '' or exit $?
    shift ; done #shift away one param ; continue loop
)

With that function you can provide as many arguments as your system will allow. If you provide fewer than 2 it will return 1 and emit a message to stderr. If you provide 2 or more arguments it will treat all as strings and return 0 if all are identical and not null else it will return 1.

In your case it can be used like:

{   
    PACKAGENAME='kakadu-v6_4-00902C'
    argeq "$PACKAGENAME" kakadu-v6_4-00902C &&
        echo "kakadu-v6_4-00902C == $PACKAGENAME" ||
        echo failure
    ! argeq "${PACKAGENAME#*-}" kakadu-v6_4-00902C &&
        echo "kakadu-v6_4-00902C != ${PACKAGENAME#*-}" ||
        echo failure
}

###OUTPUT###
kakadu-v6_4-00902C == kakadu-v6_4-00902C
kakadu-v6_4-00902C != v6_4-00902C

To demonstrate further I'll write another function:

aeqecho() { i=$((i+1))
    argeq "$@" && 
    echo "$i : yay" || 
    echo "$i : shite"
}

DEMO:

{  i= s=string
   aeqecho $s #1
   aeqecho $s $s #2
   aeqecho "$s $s" #3
   aeqecho "$s $s" "${s} string" #4
   aeqecho "${s}1" $s string #5
   aeqecho "" "" "" #6
   aeqecho "" "$s" $s #7
   aeqecho 1 "${s#$s}1" $((2-1)) #8                     
   aeqecho $s $s $s $s $s $s $s $s $s $s $s $s stng #9  
   aeqecho $s $s $s $s $s $s $s $s $s $s $s $s string #10
}  

OUTPUT:

argeq: line 2: ERR: not enough parameters!
1 : shite
2 : yay
argeq: line 2: ERR: not enough parameters!
3 : shite
4 : yay
5 : shite
6 : shite
7 : shite
8 : yay
9 : shite
10 : yay