I'm not sure exactly what conversion you want, but here's the most straightforward numerical way I came up with. It gives octets in big-endian order, which is backwards from what your example does. 
#!/usr/bin/perl

my $hexstr = "0xb400189"; 

# Convert to a number in machine-byte order
my $num = hex $hexstr;

# Convert to a number in big-endian order
my $be_num = pack("N",$num);

# Extract the 4 bytes
my($a,$b,$c,$d) = unpack("C4",$be_num);

# And print!
printf "%x.%x.%x.%x\n",$a,$b,$c,$d;

[download]
That can be simplified to a one-liner: 
printf "%x.%x.%x.%x\n", unpack("C4",pack("N",hex $hexstr));

[download]

In reply to Re: Hex to Octet by sgifford
in thread Hex to Octet by Anonymous Monk

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