dn_expand - Linux
Overview
dn_expand
is a utility that transforms a compressed Domain Name (DN) into its expanded form. It reads from standard input or a specified file and prints the expanded representation to standard output. This is useful for converting DNs stored in a compact binary format to a more readable text format.
Syntax
dn_expand [-f] [-r] [-s] [-n sep] [file]
Options/Flags
-f
: Read a flattened name format (Default).-r
: Read a relative name format.-s
: Print short names (without the terminating dot).-n sep
: Use the specifiedsep
as the separator between label values (Default: space).
Examples
Basic Usage
echo 03www06google03com | dn_expand
www.google.com.
Using Separator
echo 03www06google03com | dn_expand -n :
www:google:com
Read from File
dn_expand -f < input.txt
Common Issues
Incorrect Input Format
Ensure the input is in the correct DN format (flattened or relative). Use -f
or -r
to specify the format explicitly.
Integration
dn_expand
can be integrated with other tools to process DNS data. For example:
dig example.com | grep SOA | awk '{print $4}' | dn_expand -s
ns1.example.com.
Related Commands
dig
(DNS lookup)nslookup
(DNS lookup tool)