Sorry, it's been a long day, and my brain is cramping. 
#!/usr/bin/perl
#
#
use strict;
use warnings;

my $time  = "123456.745768";
my $time2 = "123456.745768";
$time =~ s/^(\d{2})(\d{2})(\d{2})\.(\d{2})\d{4}/$1:$2:$3.$4/;
$time2 =~ s/^(\d{2})(\d{2})(\d{2})\.(\d{2})/$1:$2:$3.$4/;

print "$time\n";
print "$time2\n";

[download]
gives me 
12:34:56.74
12:34:56.745768

[download]
Shouldn't the substitution of $time2 work? IE -- see two digits after the '.' and then leave it at that?

I even tried 
$time2 =~ s/^(\d{2})(\d{2})(\d{2})\.(\d{2}).+?/$1:$2:$3.$4/;

[download]
but got the same (bad) results.

In reply to A would-be simple substitution... by GaijinPunch

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