RkCvtHan(3) on Linux

The text d31b47eb1b12, as Debian 3.0 (Woody), Debian 2.2 (Potato), Debian 2.1 (Slink), Debian 2.0 (Hamm) shipped it.

convert double-width symbols, alphanumeric characters, hiragana, and katakana to single-width characters