$t =~ s/\/home\/roboticus\/tmp/\/home\/postgresql\/tmp/;
$t =~ s{/home/roboticus/tmp}{/home/postgresql/tmp};
$t =~ s#/home/roboticus/tmp#/home/postgresql/tmp#;

##</code><code>##

$ cat t.pl
#!/usr/bin/perl
my @a = qw(apple banana cherry durian);

my @b = grep { s#(a.)+#x#g; m/x/ } @a;
print join(", ", @b), "\n";

$ perl t.pl
xple, bxa, durix