my $word = q{thing};
$word =~ tr/i/oooo/;
__END__
thong

##</code><code>##

my $word = q{Perl is a thing I like to do.};
$word =~ s/i/oooo/;
__END__
Perl oooos a thing I like to do.

##</code><code>##

$word =~ s/i/oooo/g;
__END__
Perl oooos a thoooong I looooke to do.

##</code><code>##

my @text = split /o/, $word;
print join qq{o},@text;
__END__
Perl oooos a thoooong I looooke to do.

##</code><code>##

my @text = split /o/, $word;
print join qq{/n},@text;
__END__
Perl



s a th



ng I l



ke t
 d
.

##</code><code>##

my $line = q{Perl is a thing I like to do.};
print split /i/, $line;
print split /(i)/, $line;
__END__
Perl s a thng I lke to do.
Perl is a thing I like to do.

##</code><code>##

print join q{o}, split /i/, $line;
print join q{o}, split /(i)/, $line;
__END__
Perl os a thong I loke to do.
Perl oios a thoiong I loioke to do.

##</code><code>##

my $line = q{Perl is a thiiing I like to do.};
print join q{ooo}, split /i{2,}/, $line;
__END__
Perl is a thooong I like to do.