..

linux中的/bin与/usr/bin

有一些开源项目在make构建的时候会调用一些shell脚本，我发现这些shell脚本的shebang有一些微妙之处：

  • /usr/bin/env bash
  • /usr/bin/bash
  • /bin/bash

第一种我就不讨论了，主要是后面两种，我老是傻傻的分不清，今天找了个时间，到服务器上一看,傻眼了。 阿里云机器的centos 7

[root@iz2zefvnzjphkalt990sg0z /]# uname -a
Linux iz2zefvnzjphkalt990sg0z 3.10.0-693.2.2.el7.x86_64 #1 SMP Tue Sep 12 22:26:13 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
[root@iz2zefvnzjphkalt990sg0z /]# ll /
总用量 72
lrwxrwxrwx.  1 root root     7 10月 15 2017 bin -> usr/bin
dr-xr-xr-x.  5 root root  4096 10月 15 2017 boot
drwxr-xr-x  20 root root  3040 5月  14 18:09 dev
drwxr-xr-x. 88 root root 12288 5月  21 12:46 etc
drwxr-xr-x.  2 root root  4096 11月  5 2016 home
lrwxrwxrwx.  1 root root     7 10月 15 2017 lib -> usr/lib
lrwxrwxrwx.  1 root root     9 10月 15 2017 lib64 -> usr/lib64
drwx------.  2 root root 16384 10月 15 2017 lost+found
drwxr-xr-x.  2 root root  4096 11月  5 2016 media
drwxr-xr-x.  2 root root  4096 11月  5 2016 mnt
drwxr-xr-x.  2 root root  4096 11月  5 2016 opt
dr-xr-xr-x  73 root root     0 5月  14 18:09 proc
dr-xr-x---. 14 root root  4096 5月  21 12:45 root
drwxr-xr-x  24 root root   740 5月  21 12:54 run
lrwxrwxrwx.  1 root root     8 10月 15 2017 sbin -> usr/sbin
drwxr-xr-x   3 root root  4096 12月  9 16:30 soft
drwxr-xr-x.  3 root root  4096 12月 21 18:03 srv
dr-xr-xr-x  13 root root     0 5月  15 02:09 sys
drwxrwxrwt.  9 root root  4096 5月  21 12:52 tmp
drwxr-xr-x. 13 root root  4096 10月 15 2017 usr
drwxr-xr-x. 21 root root  4096 5月  10 16:40 var
[root@iz2zefvnzjphkalt990sg0z /]#

公司的测试环境centos 5.5

[deploy@baochai /usr]$ uname -a
Linux baochai 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
[deploy@baochai /usr]$ ll /
total 158
lrwxrwxrwx     1 root root    14 Jul 31  2015 appdata -> /data/appdata/
lrwxrwxrwx     1 root root    17 Jul 24  2015 applogs -> /data/log/applogs
dr-xr-xr-x.    2 root root  4096 Mar 14 04:46 bin
dr-xr-xr-x.    5 root root  1024 Jul 22  2015 boot
drwxr-xr-x.    2 root root  4096 Oct 18  2014 cgroup
drwxr-xr-x.   16 root root  4096 Mar  6 16:41 data
lrwxrwxrwx     1 root root    16 Jul 24  2015 deployment -> /data/deployment
drwxr-xr-x    17 root root  3700 May  8 11:08 dev
drwxr-xr-x.  118 root root 12288 May 20 03:37 etc
drwxr-xr-x.   46 root root  4096 May 15 18:00 home
dr-xr-xr-x.   11 root root  4096 Jun 14  2017 lib
dr-xr-xr-x.    9 root root 12288 Mar  7 03:27 lib64
drwx------.    2 root root 16384 Jul 22  2015 lost+found
drwxr-xr-x.    2 root root  4096 Sep 23  2011 media
drwxr-xr-x.    2 root root  4096 Nov 23  2013 misc
drwxr-xr-x.    2 root root  4096 Sep 23  2011 mnt
drwxr-xr-x.    2 root root  4096 Nov 23  2013 net
drwxr-xr-x.    6 root root  4096 Mar 28 15:59 opt
dr-xr-xr-x  1418 root root     0 Apr 29 05:19 proc
dr-xr-x---.   27 root root  4096 May 17 08:49 root
dr-xr-xr-x.    2 root root 12288 Dec 16 03:45 sbin
drwxr-xr-x.    2 root root  4096 Jul 22  2015 selinux
drwxr-xr-x.    2 root root  4096 Sep 23  2011 srv
drwxr-xr-x    13 root root     0 Apr 29 05:19 sys
drwxr-xr-x     3 root root  4096 Oct 11  2016 tep
drwsrwsrwt    60 root root 36864 May 21 14:20 tmp
drwxr-xr-x.   14 root root  4096 Jul 16  2016 usr
drwxr-xr-x.   23 root root  4096 Apr 28 15:03 var
[deploy@baochai /usr]$

WTF,在centos7下面，/bin其实就是/usr/bin，lib就是/usr/lib/,sbin就是/usr/sbin。