$ usr中/usr/bin和/usr/local/bin的顺序以及更多 [英] Order of /usr/bin and /usr/local/bin and more in $PATH

问题描述

在Mac上，我经常使用bash.对于我的环境设置，我像往常一样在$PATH中添加了/usr/bin和/usr/local/bin.

On my Mac I used bash a lot. For my environment settings I added /usr/bin and /usr/local/bin into $PATH as I normally did.

虽然我确实知道/usr/bin和/usr/local/bin是关于什么的，但我很好奇，按照惯例，哪个应该在另一个之前?并有特定的原因吗?

While I do know what /usr/bin and /usr/local/bin are about, I am curious which should go before another, by convention? And is there a specific reason for that?

与/usr/lib和/usr/local/lib类似-希望答案是相同或相似的.

Similar is for /usr/lib and /usr/local/lib -- hopefully the answer is the same or similar.

多一点- 只是原始问题的扩展，您如何按照约定在$ PATH中排序以下内容?为什么?

a bit more -- Just an extension of the original question, how would you order the following in $PATH following the convention and why?

/bin
/sbin
/usr/bin
/usr/sbin
/usr/local/bin
/usr/local/sbin
/opt/local/bin
/opt/local/sbin

推荐答案

/usr/bin是操作系统提供的二进制文件所在的位置. /usr/local/bin是用户提供的二进制文件所在的位置.在命令行上键入命令名称时，shell在$PATH环境变量 中包含的路径中搜索该命令.一个常见的模式是在$PATH中将/usr/local/bin放在/usr/bin之前.这样，您就可以安装二进制的备用版本，并使其优雅地覆盖"操作系统提供的二进制文件.而且操作系统更新不会破坏您用户安装的软件包.流行的 Homebrew 程序包管理器工具在OSX中特别使用了这种模式.

/usr/bin is where binaries supplied by the OS go. /usr/local/bin is where user supplied binaries go. When you type the name of a command on the command line, the shell searches for said command in the paths contained in the $PATH environment variable in order. A common pattern is to have /usr/local/bin precede /usr/bin in $PATH. This allows you to install alternate versions of binaries and have them gracefully "override" the binaries provided by the OS. And OS updates won't clobber your user installed packages. This pattern is notably used in OSX by the popular Homebrew package manager tool.

例如，在撰写本文时，OSX El Capitan提供git版本2.5.4(在/usr/bin中).如果您想要更新的版本，则可以使用Homebrew将git版本2.7.0(安装到/usr/local/bin中)安装.由于/usr/local/bin在$PATH环境变量中的/usr/bin之前，因此在外壳程序中发出命令git时，将使用较新的Homebrew版本.

For instance, at the time of this writing, OSX El Capitan supplies git version 2.5.4 (in /usr/bin). If you want a newer version, you can use Homebrew to install git version 2.7.0 (into /usr/local/bin). Since /usr/local/bin comes before /usr/bin in the $PATH environment variable, when you issue the command git in a shell, the newer Homebrew version will be used.

在运行OSX El Capitan(我碰巧有一个)的全新Mac上，/etc/paths文件包含以下内容:

On fresh new Mac running OSX El Capitan (I happen to have one), the /etc/paths file contains the following:

/usr/local/bin
/usr/bin
/bin
/usr/sbin
/sbin

会产生以下$PATH环境变量:

/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin

与自制软件兼容.我建议坚持使用此OSX默认设置.如果您确实要包括/usr/local/sbin(在您的问题中列出)，出于与上述类似的原因，我将其放在/usr/sbin之前.至于/opt/local/bin和/opt/local/sbin，我个人还没有发现需要将它们添加到路径中，但是似乎它们可能与/usr/local类似物相似，因为/opt传统上包含用户安装的二进制文件

which is compatible with homebrew. I recommend sticking with this OSX default. If you really want to include /usr/local/sbin (listed in your question above), I would put it just before /usr/sbin for similar reasons to above. As for /opt/local/bin and /opt/local/sbin, I haven't personally found the need to add them to the path but it seems they might go in a similar spot as their /usr/local analogs, since /opt traditionally contains user installed binaries.

注意:/usr/lib与/usr/local/lib的解释相同.

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