apt-get有几个在我看来相同的选项：autoclean,autoremove和clean. 他们每个人做什么？
由于下载损坏，Firefox 无法更新 (deb)
Preparing to unpack .../firefox_32.0+build1-0ubuntu0.14.04.1_i386.deb ...
Unpacking firefox (32.0+build1-0ubuntu0.14.04.1) over (31.0+build1-0ubuntu0.14.04.1) ...
dpkg-deb (subprocess): decompressing archive member: lzma error:
compressed data is corrupt
dpkg-deb: error: subprocess <decompress> returned error exit status 2
dpkg: error processing archive
/var/cache/apt/archives/firefox_32.0+build1-0ubuntu0.14.04.1_i386.deb (--unpack):
cannot copy extracted data for './usr/lib/firefox/libxul.so' to '/usr/lib/firefox/libxul.so.dpkg-new':
unexpected end of file or stream
Please restart all running instances of firefox, or you will experience problems.