debian下dos2unix被一到tofrodos包里面了：
apt-get install tofrodos
# dpkg -L tofrodos
/.
/usr
/usr/bin
/usr/bin/fromdos
/usr/share
/usr/share/man
/usr/share/man/man1
/usr/share/man/man1/fromdos.1.gz
/usr/share/doc
/usr/share/doc/tofrodos
/usr/share/doc/tofrodos/readme.txt.gz
/usr/share/doc/tofrodos/tofrodos.html
/usr/share/doc/tofrodos/copyright
/usr/share/doc/tofrodos/changelog.Debian.gz
/usr/bin/todos
/usr/bin/unix2dos
/usr/bin/dos2unix
/usr/share/man/man1/todos.1.gz
/usr/share/man/man1/unix2dos.1.gz
/usr/share/man/man1/dos2unix.1.gz