什么是apt passenger包安装的passenger_free_ruby可执行文件

Question

passenger_free_ruby如何运作？

我使用phusion提供的apt包安装了phusion乘客.我的系统ruby是使用brightbox apt软件包安装的ruby2.1.我希望/etc/apache2/mods-enabled/passenger.conf使用/ usr/bin/ruby​​作为PassengerDefaultRuby的默认值.它使用/ usr/bin/passenger_free_ruby.

passenger_free_ruby就像红宝石一样,是预期的红宝石

/usr/bin/passenger_free_ruby -v
ruby 2.1.6p336 (2015-04-13 revision 50298) [x86_64-linux-gnu]

如果我将ruby升级到ruby2.2,那么passenger_free_ruby就像ruby2.2一样运行

/usr/bin/passenger_free_ruby -v
ruby 2.2.2p95 (2015-04-13 revision 50295) [x86_64-linux-gnu]

那么passenger_free_ruby实际上做了什么？自由是什么意思？为什么不使用/ usr/bin/ruby​​作为默认的ruby？

Answer 1

其存在的原因记录在可执行文件的源代码中.

/*
 * This is a simple program for executing either the 'ruby' command in PATH,
 * or one of the Ruby versions installable by APT. This is necessary because
 * Debian 6 and Debian 8 (among others) do not install /usr/bin/ruby upon
 * installing one of the versioned Ruby packages (e.g. apt-get install ruby2.1).
 * Commands such as 'passenger' are supposed to be runnable under any Ruby
 * interpreter the user desires, including non-APT-installed Rubies, but we can't
 * just set the shebang line to '#!/usr/bin/env ruby'. This problem is solved by
 * setting the shebang line to '#!/usr/bin/passenger_default_ruby'.
 */