awk -F, '{
for (I=1;I<NF;I++)
{
for (J=I+1;J<=NF;J++)
{
if ($I == $J ) { print $I": " $0 }
}
}
}' << ENDOFFILE
lion,tiger,bear
apple,mango,orange,apple,grape
unix,windows,solaris,windows,linux
red,blue,green,yellow
orange,maroon,pink,violet,orange,pink
ENDOFFILE
apple: apple,mango,orange,apple,grape
windows: unix,windows,solaris,windows,linux
orange: orange,maroon,pink,violet,orange,pink
pink: orange,maroon,pink,violet,orange,pink