iconv 的說明：
NAME
iconv - Convert encoding of given files from one encoding to another
SYNOPSIS
iconv -f encoding [-t encoding] [inputfile]...
DESCRIPTION
The iconv program converts the encoding of characters in inputfile, or from the standard input if no filename is specified, from one coded character set to another. The result is
written to standard output unless otherwise specified by the --output option.
--from-code, -f encoding
Convert characters from encoding.
--to-code, -t encoding
Convert characters to encoding. If not specified the encoding corresponding to the current locale is used.
--list, -l
List known coded character sets.
-c Omit invalid characters from output.
--output, -o file
Specify output file (instead of stdout).
--silent, -s
Suppress warnings, but not errors.
--verbose
Print progress information.
--help, -?
Give help list.
--usage
Give a short usage message.
--version, -V
Print program version.iconv -f gb2312 -t utf-8 source.txt --output target.txt
