开始不知道安装啥包，后来发现在tofrodos这个包里：
sudo apt-get install tofrodos
使用方法不是unix2dos和dos2unix了，而是todos 和fromdos了。
Converts DOS <-> Unix text files, alias tofromdos
DOS text files traditionally have CR/LF (carriage return/line feed) pairs
as their new line delimiters while Unix text files traditionally have
LFs (line feeds) to terminate each line.
Tofrodos comprises one program, "fromdos" alias "todos", which converts
text files to and from these formats. Use "fromdos" to convert DOS
text files to the Unix format, and "todos" to convert Unix text files
to the DOS format.