IDN2(1) User Commands IDN2(1)

idn2 - Libidn2 Internationalized Domain Names conversion tool

idn2 [OPTION]... [STRINGS]...

The idn2 tool converts DNS domains from UTF-8 to ASCII compatible encoding (ACE) form, as used in the DNS protocol. The encoding format is the Internationalized Domain Name (IDNA2008/TR46) format.

Internationalized Domain Name (IDNA2008) convert STRINGS, or standard input.

Command line interface to the Libidn2 implementation of IDNA2008.

All strings are expected to be encoded in the locale charset.

To process a string that starts with `-', for example `-foo', use `--' to signal the end of parameters, as in `idn2 --quiet -- -foo'.

Mandatory arguments to long options are mandatory for short options too.

Print help and exit
Print version and exit
Decode (punycode) domain name
Lookup domain name (default)
Register label
Enable TR46 transitional processing
Enable TR46 non-transitional processing
Disable TR46 processing
Enable STD3 ASCII rules
Disable A-label roundtrip for lookups
Print debugging information
Silent operation

Written by Simon Josefsson, Tim Ruehsen.

Report bugs to:
Libidn2 home page:
General help using GNU software:

Copyright © 2011-2024 Simon Josefsson, Tim Ruehsen. License GPLv3+: GNU GPL version 3 or later
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.


The full documentation for idn2 is maintained as a Texinfo manual. If the info and idn2 programs are properly installed at your site, the command

info idn2

should give you access to the complete manual.

January 2024 Libidn2 2.3.7