Maybe File::Data will be usefull for you:

use File::Data;

use strict;
use File::Data;

my $o_dat = File::Data->new('./t/example');
$o_dat->write("complete file contents\n");
$o_dat->prepend("first line\n"); # line 0
$o_dat->append("original second (last) line\n");
$o_dat->insert(2, "new second line\n"); # inc. zero!
$o_dat->replace('line', 'LINE');
print $o_dat->READ;
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SV* sv_bless(SV* sv, HV* stash);