$ cat pm_1189607_input
old/path/to/some/file
another/old/path/to/some/file
one/more/old/path/to/some/file
path/to/keep/as/is/file
$ pm_1189607_read_replace_write.pl
$ cat pm_1189607_output
new/path/to/some/file
another/new/path/to/some/file
one/more/new/path/to/some/file
path/to/keep/as/is/file
$