my $str = "jigglewort";
my @a = split //, $str;
print join('',@a[0..$_-1, $_+1, $_, $_+2..$#a]),"\n" for 0..$#a;

##</code><code>##

ijgglewort
jgiglewort
jigglewort
jiglgewort
jiggelwort
jigglweort
jiggleowrt
jigglewrot
jigglewotr
jigglewort