man apt-get
apt-get install python-opencv #安装python-opencv
apt-get remove python-opencv #卸载python-opencv
apt-get update #从/etc/apt/sources.list 更新apt-cache
apt-get upgrade #从/etc/apt/sources.list 更新apt-cache，同时cache更新软件man apt-cache
/var/lib/apt/lists/mirrors.tuna.tsinghua.edu.cn_debian_dists_jessie_main_binary-arm64_Packages
apt-cache showpkg python-opencv
apt-cache show python-pencvman sources.list
EXAMPLES
Uses the archive stored locally (or NFS mounted) at /home/jason/debian for stable/main, stable/contrib, and stable/non-free.
deb file:/home/jason/debian stable main contrib non-free
As above, except this uses the unstable (development) distribution.
deb file:/home/jason/debian unstable main contrib non-free
Source line for the above
deb-src file:/home/jason/debian unstable main contrib non-free
The first line gets package information for the architectures in APT::Architectures while the second always retrieves amd64 and armel.
deb http://ftp.debian.org/debian jessie main
deb [ arch=amd64,armel ] http://ftp.debian.org/debian jessie main
Uses HTTP to access the archive at archive.debian.org, and uses only the hamm/main area.
deb http://archive.debian.org/debian-archive hamm main
Uses FTP to access the archive at ftp.debian.org, under the debian directory, and uses only the jessie/contrib area.
deb ftp://ftp.debian.org/debian jessie contrib
Uses FTP to access the archive at ftp.debian.org, under the debian directory, and uses only the unstable/contrib area. If this line appears as well as the one in the previous example in
sources.list a single FTP session will be used for both resource lines.
deb ftp://ftp.debian.org/debian unstable contrib
Uses HTTP to access the archive at ftp.tlh.debian.org, under the universe directory, and uses only files found under unstable/binary-i386 on i386 machines, unstable/binary-amd64 on amd64, and so
forth for other supported architectures. [Note this example only illustrates how to use the substitution variable; official debian archives are not structured like this]
deb http://ftp.tlh.debian.org/universe unstable/binary-$(ARCH)/