1. whereis python3 不显示命令的路径，但是python3 可用
不知什么时候安装的python3，但是
$ whereis python
/usr/bin/python
$ whereis python3
$ python3
Python 3.6.5 (default, Jun 17 2018, 12:13:06)
[GCC 4.2.1 Compatible Apple LLVM 9.1.0 (clang-902.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>
$ which python3
/usr/local/bin/python3
2. which 和whereis 区别
-
which
在$PATH变量下找到可运行的程序
$ man which
WHICH(1) BSD General Commands Manual WHICH(1)
NAME
which -- locate a program file in the user's path
SYNOPSIS
which [-as] program ...
DESCRIPTION
The which utility takes a list of command names and searches the path for each executable file
that would be run had these commands actually been invoked.
The following options are available:
-a List all instances of executables found (instead of just the first one of each).
-
whereis
在标准二进制文件夹 下寻找特定的程序
$ man whereis
WHEREIS(1) BSD General Commands Manual WHEREIS(1)
NAME
whereis -- locate programs
SYNOPSIS
whereis [program ...]
DESCRIPTION
The whereis utility checks the standard binary directories for the specified programs, print-
ing out the paths of any it finds.
The path searched is the string returned by the sysctl(8) utility for the ``user.cs_path''
string.
3. homebrew 安装的python3
Homebrew 将软件包分装到单独的目录（/usr/local/Cellar）
$ ll /usr/local/bin/python3
lrwxr-xr-x 1 36B 6 29 12:43 python3 -> ../Cellar/python/3.6.5_1/bin/python3
$ ll /usr/local/Cellar/python/3.6.5_1
lrwxr-xr-x 1 wheel 18B 3 28 18:24 Headers -> include/python3.6m
-r-xr-xr-x 1 wheel 2.1M 6 29 12:43 Python
drwxr-xr-x 4 wheel 128B 3 28 18:24 Resources
drwxr-xr-x 16 wheel 512B 6 29 12:43 bin
drwxr-xr-x 3 wheel 96B 3 28 18:24 include
drwxr-xr-x 6 wheel 192B 3 28 18:24 lib
drwxr-xr-x 3 wheel 96B 3 28 18:24 share
