IDN2(1) IDN2(1)
July 2017
NAME
idn2 - Libidn2 Internationalized Domain Names conversion tool
SYNOPSIS
idn2 [OPTION]... [STRINGS]...
DESCRIPTION
idn2 tool converts DNS domains from UTF-8 to ASCII compatibile
encoding (ACE) form, as used in the DNS protocol. The encoding format
is the Internationalized Domain Name (IDNA2008/TR46) format.
All input 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.
-h, --help
Prints help and exits.
-V, --version
Prints version and exits.
-d, --decode
Decode an ACE name according to IDNA2008.
-l, --lookup
Encode to ACE according to IDNA2008 (the default).
-r, --register
Registers a label.
-T, --tr46t
Enable TR#46 transitional processing.
-N, --tr46nt
Enable TR#46 non-transitional processing (default).
--no-tr46
Disable TR#46 processing.
--usestd3asciirules
Enable STD3 ASCII rules.
--debug
Prints debugging information.
--quiet
Silent operation.
- 1 - Formatted: December 15, 2025
IDN2(1) IDN2(1)
July 2017
Author
Written by Simon Josefsson.
Reporting bugs
Report bugs to the gitlab issue tracker of the project
https://gitlab.com/libidn/libidn2/issues.
- 2 - Formatted: December 15, 2025
