$ update-alternatives --help
Usage: update-alternatives [<option> ...] <command>
Commands:
--install <link> <name> <path> <priority>
[--slave <link> <name> <path>] ...
add a group of alternatives to the system.
--remove <name> <path> remove <path> from the <name> group alternative.
--remove-all <name> remove <name> group from the alternatives system.
--auto <name> switch the master link <name> to automatic mode.
--display <name> display information about the <name> group.
--query <name> machine parseable version of --display <name>.
--list <name> display all targets of the <name> group.
--get-selections list master alternative names and their status.
--set-selections read alternative status from standard input.
--config <name> show alternatives for the <name> group and ask the
user to select which one to use.
--set <name> <path> set <path> as alternative for <name>.
--all call --config on all alternatives.
<link> is the symlink pointing to /etc/alternatives/<name>.
(e.g. /usr/bin/pager)
<name> is the master name for this link group.
(e.g. pager)
<path> is the location of one of the alternative target files.
(e.g. /usr/bin/less)
<priority> is an integer; options with higher numbers have higher priority in
automatic mode.
Options:
--altdir <directory> change the alternatives directory.
--admindir <directory> change the administrative directory.
--log <file> change the log file.
--force allow replacing files with alternative links.
--skip-auto skip prompt for alternatives correctly configured
in automatic mode (relevant for --config only)
--quiet quiet operation, minimal output.
--verbose verbose operation, more output.
--debug debug output, way more output.
--help show this help message.
--version show the version.
UseCase
--display
$ update-alternatives --display python
python - 手动模式
link best version is /usr/bin/python3.5
链接目前指向 /usr/bin/python2.7
link python is /usr/bin/python
/usr/bin/python2.7 - 优先级 1
/usr/bin/python3.5 - 优先级 2
updatealternatives 多版本软件管理工具
UseCase
--display
--install
--config
--remove
应用
Reference