NKF(3pm)

📦
version 2.1.5 · 11 versions
, in ubuntu stonking

💖 NAME 💖

okay so bestie, welcome to NKF(3pm) 💅 this is the page for nkf — a kanji code converter that hops between networks, hosts and terminals — as it shows up in the Perl world (see the little nkf(...) call down below, iykyk). Sit down, grab a strawberry 🍓, and let's get you fluent.

✨ SYNOPSIS ✨

ngl there's no big synopsis flex at the top of this one — the whole vibe lives in DESCRIPTION and OPTIONS right underneath. Scroll, queen 👑

🦋 DESCRIPTION 🦋

Nkf is a yet another kanji code converter among networks, hosts and terminals. Like, it takes your input kanji code and converts it to the designated kanji code — things like ISO-2022-JP, Shift_JIS, EUC-JP, UTF-8, UTF-16 or UTF-32. periodt.

One of the most unique faculty of nkf is the guess of the input kanji encodings 🔮 It currently recognizes ISO-2022-JP, Shift_JIS, EUC-JP, UTF-8, UTF-16 and UTF-32. So users needn't set the input kanji code explicitly. it just knows. main character energy fr fr.

By default, X0201 kana is converted into X0208 kana. For X0201 kana, SO/SI, SSO and ESC-(-I methods are supported. For automatic code detection, nkf assumes no X0201 kana in Shift_JIS. To accept X0201 in Shift_JIS, use -X, -x or -S. ✍️

multiple options are specifed as seprate strings, such as

print nkf('--ic=UTF8-MAC', '-w', $string), "\n";

except the last arguments. (yeah, sneak that last one in there, she's special 💅)

👑 OPTIONS 👑

🎀 Encodings, in and out

  • -J, -S, -E, -W, -W16, -W32, -j, -s, -e, -w, -w16, -w32 — Specify input and output encodings. Upper case is input. cf. --ic and --oc.
    • -J — ISO-2022-JP (JIS code).
    • -S — Shift_JIS and JIS X 0201 kana. EUC-JP is recognized as X0201 kana. Without -x flag, JIS X 0201 Katakana (a.k.a.halfwidth kana) is converted into JIS X 0208. If you use Windows, see Windows-31J (CP932).
    • -E — EUC-JP.
    • -W — UTF-8N.
    • -W16[BL][0] — UTF-16. B or L gives whether Big Endian or Little Endian. 0 gives whther put BOM or not.
    • -W32[BL][0] — UTF-32. B or L gives whether Big Endian or Little Endian. 0 gives whther put BOM or not.

🌸 Buffering & chill

  • -b, -u — Output is buffered (DEFAULT), Output is unbuffered.
  • -t — No conversion. just vibes, untouched ✨

🧚 Escape sequences & friends

  • -i[@B] — Specify the escape sequence for JIS X 0208.
    • -i@ — Use ESC ( @. (JIS X 0208-1978)
    • -iB — Use ESC ( B. (JIS X 0208-1983/1990 DEFAULT)
  • -o[BJ] — Specify the escape sequence for US-ASCII/JIS X 0201 Roman. (DEFAULT B)
  • -r — {de/en}crypt ROT13/47 🕵️

💅 Kana glow-ups

  • -h[123], --hiragana, --katakana, --katakana-hiragana
    • -h1, --hiragana — Katakana to Hiragana conversion.
    • -h2, --katakana — Hiragana to Katakana conversion.
    • -h3, --katakana-hiragana — Katakana to Hiragana and Hiragana to Katakana conversion.

🫶 Output modes & folding

  • -T — Text mode output (MS-DOS)
  • -f[m [- n]] — Folding on m length with n margin in a line. Without this option, fold length is 60 and fold margin is 10.
  • -F — New line preserving line folding.

🔥 Fullwidth alphabet shenanigans

  • -Z[0-3] — Convert X0208 alphabet (Fullwidth Alphabets) to ASCII.
    • -Z, -Z0 — Convert X0208 alphabet to ASCII.
    • -Z1 — Convert X0208 kankaku to single ASCII space.
    • -Z2 — Convert X0208 kankaku to double ASCII spaces.
    • -Z3 — Replacing fullwidth >, <, ", & into '&gt;', '&lt;', '&quot;', '&amp;' as in HTML.

🌈 X0201 kana policy

  • -X, -x — With -X or without this option, X0201 is converted into X0208 Kana. With -x, try to preserve X0208 kana and do not convert X0201 kana to X0208. In JIS output, ESC-(-I is used. In EUC output, SS2 is used.

💀 Broken-JIS rescue mission

  • -B[0-2] — Assume broken JIS-Kanji input, which lost ESC. Useful when your site is using old B-News Nihongo patch.
    • -B1 — allows any chars after ESC-( or ESC-$.
    • -B2 — force ASCII after NL.

🎀 geta character moment

  • -I — Replacing non iso-2022-jp char into a geta character (substitute character in Japanese).

🍓 MIME decode

  • -m[BQN0] — MIME ISO-2022-JP/ISO8859-1 decode. (DEFAULT) To see ISO8859-1 (Latin-1) -l is necessary.
    • -mB — Decode MIME base64 encoded stream. Remove header or other part before conversion.
    • -mQ — Decode MIME quoted stream. '_' in quoted stream is converted to space.
    • -mN — Non-strict decoding. It allows line break in the middle of the base64 encoding.
    • -m0 — No MIME decode.

⭐ MIME encode

  • -M — MIME encode. Header style. All ASCII code and control characters are intact.
    • -MB — MIME encode Base64 stream. Kanji conversion is performed before encoding, so this cannot be used as a picture encoder.
    • -MQ — Perform quoted encoding.

💜 Latin-1 (with boundaries, bestie)

  • -l — Input and output code is ISO8859-1 (Latin-1) and ISO-2022-JP. -s, -e and -x are not compatible with this option.

🧚 Line break control

  • -L[uwm], -d, -c — Convert line breaks.
    • -Lu, -d — unix (LF)
    • -Lw, -c — windows (CRLF)
    • -Lm — mac (CR)
Without this option, nkf doesn't convert line breaks. 🚨

✨ System presets

  • --fj, --unix, --mac, --msdos, --windows — Convert for these systems.
  • --jis, --euc, --sjis, --mime, --base64 — Convert to named code.
  • --jis-input, --euc-input, --sjis-input, --mime-input, --base64-input — Assume input system

🌸 The codeset menu

  • --ic=input codeset, --oc=output codeset — Set the input or output codeset. NKF supports following codesets and those codeset names are case insensitive.
    • ISO-2022-JP — a.k.a. RFC1468, 7bit JIS, JUNET
    • EUC-JP (eucJP-nkf) — a.k.a. AT&T JIS, Japanese EUC, UJIS
    • eucJP-ascii
    • eucJP-ms
    • CP51932 — Microsoft Version of EUC-JP.
    • Shift_JIS — a.k.a. SJIS, MS_Kanji
    • Windows-31J — a.k.a. CP932
    • UTF-8 — same as UTF-8N
    • UTF-8N — UTF-8 without BOM
    • UTF-8-BOM — UTF-8 with BOM
    • UTF8-MAC (input only) — decomposed UTF-8
    • UTF-16 — same as UTF-16BE
    • UTF-16BE — UTF-16 Big Endian without BOM
    • UTF-16BE-BOM — UTF-16 Big Endian with BOM
    • UTF-16LE — UTF-16 Little Endian without BOM
    • UTF-16LE-BOM — UTF-16 Little Endian with BOM
    • UTF-32 — same as UTF-32BE
    • UTF-32BE — UTF-32 Big Endian without BOM
    • UTF-32BE-BOM — UTF-32 Big Endian with BOM
    • UTF-32LE — UTF-32 Little Endian without BOM
    • UTF-32LE-BOM — UTF-32 Little Endian with BOM

🫶 Unassigned characters & byte etiquette

  • --fb-{skip, html, xml, perl, java, subchar} — Specify the way that nkf handles unassigned characters. Without this option, --fb-skip is assumed.
  • --prefix=escape charactertarget character.. — When nkf converts to Shift_JIS, nkf adds a specified escape character to specified 2nd byte of Shift_JIS characters. 1st byte of argument is the escape character and following bytes are target characters.
  • --no-cp932ext — Handle the characters extended in CP932 as unassigned characters.
  • --no-best-fit-chars — When Unicode to Encoded byte conversion, don't convert characters which is not round trip safe. When Unicode to Unicode conversion, with this and -x option, nkf can be used as UTF converter. (In other words, without this and -x option, nkf doesn't save some characters)
When nkf converts strings that related to path, you should use this opion. 👀
  • --cap-input — Decode hex encoded characters.
  • --url-input — Unescape percent escaped characters.
  • --numchar-input — Decode character reference, such as "&#....;".
  • -- — Ignore rest of -option.

🌈 AUTHOR 🌈

Copyright (c) 1987, Fujitsu LTD. (Itaru ICHIKAWA).

Copyright (c) 1996-2018, The nkf Project.

and that's the whole page, bestie 💖 this was NKF(3pm) from the User Contributed Perl Documentation collection, shipped as perl v5.42.3 on 2026-08-20 — go forth and convert, you absolute icon ✨👑🦋🎀

📦 where this page comes from