nkf
Network kanji filter.
TLDR
Convert to UTF-8 encoding
$ nkf -w [path/to/file.txt]
Convert to SHIFT_JIS encoding
$ nkf -s [path/to/file.txt]
Convert to UTF-8 encoding and overwrite the file
$ nkf -w --overwrite [path/to/file.txt]
Use LF as the new line code and overwrite (UNIX type)
$ nkf -d --overwrite [path/to/file.txt]
Use CRLF as the new line code and overwrite (windows type)
$ nkf -c --overwrite [path/to/file.txt]
Decrypt mime file and overwrite
$ nkf -m --overwrite [path/to/file.txt]