课程第5次

botang

2019-04-15星期一

关于文件系统的小练习：

1. -bash-4.2# mkdir labs
   
2. -bash-4.2# ls
   
3. 1.txt  Desktop  Documents  Downloads  labs  Music  Pictures  Public  Templates  Videos
   
4. -bash-4.2# cd labs
   
5. -bash-4.2# ls
   
6. -bash-4.2# touch "1 space 2"
   
7. -bash-4.2# mkdir "3 space 4"
   
8. -bash-4.2# ls
   
9. 1 space 2  3 space 4
   
10. -bash-4.2# cd 3\ space\ 4/
    
11. -bash-4.2# touch " "
    
12. -bash-4.2# ls
    
13. 
    
14. -bash-4.2# ls
    
15. 
    
16. -bash-4.2# cd ..
    
17. -bash-4.2# ls
    
18. 1 space 2  3 space 4
    
19. -bash-4.2# cd 3\ space\ 4/
    
20. -bash-4.2# ls
    
21. 
    
22. -bash-4.2# ls -l | wc -l
    
23. 2
    
24. -bash-4.2# cd ..
    
25. -bash-4.2# ls
    
26. 1 space 2  3 space 4
    
27. -bash-4.2# mkdir 5
    
28. -bash-4.2# cd 5
    
29. -bash-4.2# ls -l | wc -l
    
30. 1
    

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文件、文件夹的3个时间的小实验：

1. [root@station60 labs]# touch 5.sh
   
2. [root@station60 labs]# stat 5.sh
   
3.   File: ‘5.sh’
   
4.   Size: 11              Blocks: 8          IO Block: 4096   regular file
   
5. Device: fd00h/64768d    Inode: 82810       Links: 1
   
6. Access: (0755/-rwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
   
7. Context: unconfined_u:object_r:admin_home_t:s0
   
8. Access: 2019-04-15 08:53:37.254822442 -0400
   
9. Modify: 2019-04-15 08:53:37.254822442 -0400
   
10. Change: 2019-04-15 08:53:37.254822442 -0400
    
11. Birth: -
    
12. [root@station60 labs]# echo "123456"  >> 5.sh
    
13. [root@station60 labs]# stat 5.sh
    
14.   File: ‘5.sh’
    
15.   Size: 18              Blocks: 8          IO Block: 4096   regular file
    
16. Device: fd00h/64768d    Inode: 82810       Links: 1
    
17. Access: (0755/-rwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
    
18. Context: unconfined_u:object_r:admin_home_t:s0
    
19. Access: 2019-04-15 08:53:37.254822442 -0400
    
20. Modify: 2019-04-15 08:54:08.817003129 -0400
    
21. Change: 2019-04-15 08:54:08.817003129 -0400
    
22. Birth: -
    
23. [root@station60 labs]# chmod 777 5.sh
    
24. [root@station60 labs]# stat 5.sh
    
25.   File: ‘5.sh’
    
26.   Size: 18              Blocks: 8          IO Block: 4096   regular file
    
27. Device: fd00h/64768d    Inode: 82810       Links: 1
    
28. Access: (0777/-rwxrwxrwx)  Uid: (    0/    root)   Gid: (    0/    root)
    
29. Context: unconfined_u:object_r:admin_home_t:s0
    
30. Access: 2019-04-15 08:53:37.254822442 -0400
    
31. Modify: 2019-04-15 08:54:08.817003129 -0400
    
32. Change: 2019-04-15 08:54:34.540150391 -0400
    
33. Birth: -
    

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隐含文件和执行位的小实验：

1. [root@station60 labs]# vim .6.sh
   
2. [root@station60 labs]# ls
   
3. ！  1.sh  2.sh  4.sh  5.sh
   
4. [root@station60 labs]# ls -a
   
5. .  ..  ！  1.sh  2.sh  4.sh  5.sh  .6.sh
   
6. [root@station60 labs]# chmod +x .6.sh
   
7. [root@station60 labs]# ./.6.sh
   
8. Mon Apr 15 09:01:55 EDT 2019
   

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命令行扩展和文件通配符很相似，但不同：

1. [root@station60 ~]# cd -
   
2. bash: cd: OLDPWD not set
   
3. [root@station60 ~]# echo -
   
4. -
   
5. [root@station60 ~]# echo ~+
   
6. /root
   
7. [root@station60 ~]# cd /usr/sbin
   
8. [root@station60 sbin]# echo ~-
   
9. /root
   
10. [root@station60 sbin]# echo ~+
    
11. /usr/sbin
    
12. [root@station60 sbin]# cd -
    
13. /root
    
14. [root@station60 ~]# cd -
    
15. /usr/sbin
    
16. [root@station60 sbin]#
    

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cd -是命令行扩展
cd ~+ 是文件通配符第二个例子，以下命令为什么会失败？

1. [root@station60 sbin]# cd
   
2. [root@station60 ~]# ls
   
3. anaconda-ks.cfg  Documents  initial-setup-ks.cfg  Music     Public     Videos
   
4. Desktop          Downloads  labs                  Pictures  Templates
   
5. [root@station60 ~]# find ./ -name  P*
   
6. find: paths must precede expression: Public
   
7. Usage: find [-H] [-L] [-P] [-Olevel] [-D help|tree|search|stat|rates|opt|exec] [path...] [expression]
   

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原因是P* 先被通配成了find ./ -name  Public   Pictures 导致语法错了

1. [root@station60 ~]# find ./ -name  "P*"
   
2. ./Public
   
3. ./Pictures
   

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有歧义的命令行扩展和文件通配符：

1. [root@station60 ~]# cd labs
   
2. [root@station60 labs]# ls
   
3. ！  1.sh  2.sh  4.sh  5.sh
   
4. [root@station60 labs]# ls [12345].sh
   
5. 1.sh  2.sh  4.sh  5.sh
   
6. [root@station60 labs]# touch [12345].sh
   
7. [root@station60 labs]# ls
   
8. ！  1.sh  2.sh  4.sh  5.sh
   
9. [root@station60 labs]# touch *[12345].sh
   
10. [root@station60 labs]# ls
    
11. ！  1.sh  2.sh  4.sh  5.sh
    
12. [root@station60 labs]# mkdir [abcd]
    
13. [root@station60 labs]# ls
    
14. ！  1.sh  2.sh  4.sh  5.sh  [abcd]
    
15. [root@station60 labs]# mkdir {a,b,c,d}
    
16. [root@station60 labs]# ls
    
17. ！  1.sh  2.sh  4.sh  5.sh  a  [abcd]  b  c  d
    
18. [root@station60 labs]# touch {1,2,3,4,5}
    
19. [root@station60 labs]# ls
    
20. ！  1  1.sh  2  2.sh  3  4  4.sh  5  5.sh  a  [abcd]  b  c  d
    

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$()是最重要的命令行扩展，它这么处理输出中的回车？

1. [root@station60 /]# ls -d  *
   
2. bin   dev  home  lib64       media  opt   root  sbin  sys  usr
   
3. boot  etc  lib   lost+found  mnt    proc  run   srv   tmp  var
   
4. [root@station60 /]# echo $(ls -d *)
   
5. bin boot dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var
   

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1. [root@station60 labs]# cat list.txt
   
2. a
   
3. b
   
4. c
   
5. d
   
6. e
   
7. f
   
8. [root@station60 labs]# echo $(cat list.txt)
   
9. a b c d e f
   
10. [root@station60 labs]# for i in $(cat list.txt); do echo $i; done
    
11. a
    
12. b
    
13. c
    
14. d
    
15. e
    
16. f
    

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对变量名本身的区分：

1. [root@station60 labs]# host=$(hostname)
   
2. [root@station60 labs]# echo $host
   
3. station60.example.com
   
4. [root@station60 labs]# host1=$(date)
   
5. [root@station60 labs]# echo $host1
   
6. Mon Apr 15 10:37:21 EDT 2019
   
7. [root@station60 labs]# echo ${host}1
   
8. station60.example.com1
   
9. [root@station60 labs]# echo ${host1}
   
10. Mon Apr 15 10:37:21 EDT 2019
    

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单引号的 限制能力最强：

1. [root@station60 labs]# echo ${host1}
   
2. Mon Apr 15 10:37:21 EDT 2019
   
3. [root@station60 labs]# echo "${host1}"
   
4. Mon Apr 15 10:37:21 EDT 2019
   
5. [root@station60 labs]# echo '${host1}'
   
6. ${host1}
   
7. [root@station60 labs]#
   

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rhce小学徒海涛

linhaitao@localhost ~]$ cd labs
[linhaitao@localhost labs]$ ls
[linhaitao@localhost labs]$ touch "1space 2"
[linhaitao@localhost labs]$ mkdir "3 space 4"
[linhaitao@localhost labs]$ ls
1space 2  3 space 4
[linhaitao@localhost labs]$ cd 3\ space\ 4/
[linhaitao@localhost 3 space 4]$ touch""
touch: 缺少了文件操作数
Try 'touch --help' for more information.
[linhaitao@localhost 3 space 4]$ touch ""
touch: 无法创建"": 没有那个文件或目录
[linhaitao@localhost 3 space 4]$
悲剧啊为啥我做这个到这边出现这个

botang

rhce小学徒海涛 发表于 2019-4-17 20:01
linhaitao@localhost ~]$ cd labs
[linhaitao@localhost labs]$ ls
[linhaitao@localhost labs]$ touch " ...

touch " ", 注意空格