The Three Musketeers and common commands of Linux

Symbols to keep in mind:

>
2>>
2>&1

6.1 Move the/data to the/root directory
#move MV

[Email protected] ~]# mv/data//root/
[Email protected] ~]# ls-l/data
Ls:cannot access/data:no such file or directory
[Email protected] ~]# ls-l/root/
Total 44
-RW-------. 1 root root 1124 Jul 18:25 anaconda-ks.cfg
Drwxr-xr-x. 2 root root 4096 Jul 02:13 data
-rw-r--r--. 1 root root 21736 Jul 18:25 Install.log
-rw-r--r--. 1 root root 5890 Jul 18:24 install.log.syslog

6.2 "Piping Concept" Enter the data directory under the/root directory to delete the Oldboy.txt file

Instance 6-1 #如何备份?
[[email protected] ~]# cd/root/data/
[[email protected] data]# pwd
/root/data
[[email  Protected] data]# ls-l
Total
-rw-r--r--. 1 root root 7 Jul 02:13 alex.txt
-rw-r--r--. 1 root root Jul 1 1 01:16 lidao.txt
-rw-r--r--. 1 root root 254 Jul 01:08 oldboy.txt
[[email protected] data]# CP oldboy.txt O Ldboy.txt.bak
[[email protected] data]# ls-l
Total
-rw-r--r--. 1 root root 7 Jul 02:13 alex.txt
-R W-r--r--. 1 root root 01:16 lidao.txt
-rw-r--r--. 1 root root 254 Jul 01:08 oldboy.txt
-rw-r--r--. 1 root root 25 4 Jul 02:56 Oldboy.txt.bak

. bak = = = Backup
Instance 6-2 #修改文件名 renaming
[Email protected] data]# MV Oldboy.txt oldgirl.txt
[Email protected] data]# ls-l
Total 16
-rw-r--r--. 1 root root 7 Jul 02:13 alex.txt
-rw-r--r--. 1 root root 01:16 lidao.txt
-rw-r--r--. 1 root root 254 Jul 02:56 Oldboy.txt.bak
-rw-r--r--. 1 root root 254 Jul 01:08 oldgirl.txt

6.3 #强制删除
[Email protected] data]# rm-f/root/data/oldgirl.txt
[Email protected] data]# ls-l/root/data/
Total 12
-rw-r--r--. 1 root root 7 Jul 02:13 alex.txt
-rw-r--r--. 1 root root 01:16 lidao.txt
-rw-r--r--. 1 root root 254 Jul 02:56 Oldboy.txt.bak

6.4 #强制删除目录
[Email protected] data]# rm-rf/tmp/data/
[Email protected] data]# ls-l/tmp/data
Ls:cannot access/tmp/data:no such file or directory

rm-rf/tmp/data/
rm-fr/tmp/data/

6.5 #怎么样防止 mistakenly deleted

#创建环境

Touch/root/oldboy.txt/root/alex.txt/root/lidao.txt

6.6 #find命令
[[email protected] data]# #find in xxx-type F-Name "Oldboy.txt"
[Email protected] data]#
[Email protected] data]# find/root/-type f-name "Oldboy.txt"
/root/oldboy.txt

-type what type of f file (file) to find
d Directory (directory)
-name "What's the name?"

#喜欢送/root files ending in. txt
Oldboy.txt Lidao.txt Alex.txt
6.7 Fuzzy Lookup
[Email protected] data]# find/root/-type f-name ".txt"
/root/oldboy.txt
/root/lidao.txt
/root/alex.txt
/root/data/lidao.txt
/root/data/alex.txt
[[Email protected] data]# # Any character of any character

[Email protected] data]# find/root/-type f-name ".txt"
/root/oldboy.txt
/root/lidao.txt
/root/alex.txt
/root/data/lidao.txt
/root/data/alex.txt
6.8 Piping
[Email protected] data]# find/root/-type f-name ". txt" |xargs ls-l
-rw-r--r--. 1 root root 0 Jul 03:21/root/alex.txt
-rw-r--r--. 1 root root 7 Jul 02:13/root/data/alex.txt
-rw-r--r--. 1 root root 01:16/root/data/lidao.txt
-rw-r--r--. 1 root root 0 Jul 03:21/root/lidao.txt
-rw-r--r--. 1 root root 0 Jul 03:21/root/oldboy.txt

Find +|xargs Mates
| different from |xargs
Old boy Education Daily-May 18, 2017-Talk | The difference between (piping) and |xargs (pipe Xargs)
http://blog.51cto.com/lidao/1927347

#7 Answer question 6th, exit to the previous level directory to delete the data directory. (originally in/root/data)
Cd.. Go to the top level directory of the current directory
Cd. Go to current directory
#移动xxxxx文件 to the current directory
#复制xxxxx文件 to the current directory
[Email protected] tmp]# cp/root/oldboy.txt.
Cp:overwrite './oldboy.txt '? Y
[Email protected] tmp]# ls-l
Total 4
-rw-r--r--. 1 root root 17:01 oldboy.txt
-RW-------. 1 root root 0 Jul 16:19 yum.log

6.9 Entering the current directory

[Email protected]/]# cd/root/data/
[Email protected] data]# pwd
/root/data
[Email protected] data]# cp/root/oldboy.txt.

4.8 Known files test.txt content
Test
Lidao
Oldboy
To create a test file:
Mkdir-p/data
Cat >/data/test.txt<<eof
Test
Liyao
Oldboy
Eof
6.10 Please give the command that does not contain the Oldboy string when outputting the contents of the Test.txt file.

Example 6-3 method 1-grep
[[email protected] data]# #grep filter to show what you want or not
[[email protected] data]# grep "Oldboy"/data/test.txt
Oldboy
[Email protected] data]# grep-v "Oldboy"/data/test.txt
Test
Liyao

Method 2-head
[Email protected] data]# Head-n2/data/test.txt
Test
Liyao
[Email protected] data]# head-2/data/test.txt
Test
Liyao

#head shows the first few lines of the file display the first 10 rows by default
#tail display the last few lines of the file display the last 10 lines by default

6.11 #显示文件最后一行
[Email protected] data]# tail-1/data/test.txt
Oldboy

Instance 6-4 #方法3 awk
[Email protected] data]# #awk
[Email protected] data]# #gawk
[Email protected] data]# awk '/oldboy/'/data/test.txt
Oldboy
[Email protected] data]# awk '!/oldboy/'/data/test.txt
Test
Liyao

Example 6-5 #方法4 sed
[[Email protected] data]# sed '/oldboy/d '/data/test.txt
Test
Liyao
[Email protected] data]# #delete

Summary:
1.grep Filtration
2.head Tail
3.sed awk (Learn)

6.12 #9 Use a command to complete the creation of the directory/oldboy/test, which is to create/oldboy directory and/oldboy/test

[Email protected] data]# mkdir-p/oldboy/test
[Email protected] data]# ls/oldboy/
Test
#-p creating a multi-level catalog

6.13 #11 View only the contents of rows 20th through 30th in the Ett.txt file (total 100 lines)

[[email protected] data]# SEQ 10
1
2
3
4
5
6
7
8
9
10

SEQ->/data/ett.txt

Example 6-6 #方法1 head + tail
[Email protected] data]# Head-30/data/ett.txt |tail
21st
22
23
24
25
26
27
28
29
30
[Email protected] data]# Head-30/data/ett.txt |tail-11
20
21st
22
23
24
25
26
27
28
29
30

6.14 #显示文件的第30到40行
Key commands:
(1). Head-40/data/ett.txt |tail-11
(2). Tail-11/data/ett.txt

Instance 6-7 #方法2 sed fetch line
[Email protected] data]# sed-n ' 3p '/data/ett.txt
3
#-n Cancel default output (SED command does not display the contents of the file)
[Email protected] data]# sed-n ' 3p '/data/ett.txt
3
#print (meaning shown)
[Email protected] data]# sed-n ' 20p '/data/ett.txt
20

6.15 take 20 lines to 30 rows
[Email protected] data]# sed-n ' 20,30p '/data/ett.txt
20
21st
22
23
24
25
26
27
28
29
30

Instance 6-8 #方法3 awk
[Email protected] data]# awk ' nr==3 '/data/ett.txt
3
[[Email protected] data]# # ' nr line number equals 3 '
[Email protected] data]# awk ' nr==20,nr==30 '/data/ett.txt
20
21st
22
23
24
25
26
27
28
29
30

Mv
[Email protected] ~]# MV Oldboy.txt oldgirl.txt
[Email protected] ~]# ls-l
Total 44
-RW-------. 1 root root 1133 Jul 16:23 anaconda-ks.cfg
-rw-r--r--. 1 root root 21736 Jul 16:23 Install.log
-rw-r--r--. 1 root root 5890 Jul 16:22 install.log.syslog
-rw-r--r--. 1 root root 15:29 oldgirl.txt

6.16 How do I back up?
CD Backup

6.17 RM Delete File
Rm-f forcing files to be deleted
Rm–r Deleting a directory
RM–RF forcibly deleting a directory
RM–FR forcibly deleting a directory

Attention
[Email protected] data]# # "": "".
[[Email protected] data]# # "": <<>>.

6.18 How to prevent accidental deletion
Create an environment
Find Lookup
[Email protected] ~]# find/root/-type f-name "Oldboy.txt"
/root/oldboy.txt
[Email protected] ~]#
Find Fuzzy Lookup
[Email protected] ~]# find/root/-type f-name ".txt"
/root/oldboy.txt
/root/oldgirl.txt
What type of-type to look for
F Fire (file)
d Directory (directory)
-name (first name)
6.19 Pipe (Prevent accidental deletion)
[Email protected] ~]# find/root/-type f-name ". txt" |xargs ls-l
-rw-r--r--. 1 root root 0 Jul 15:56/root/oldboy.txt
-rw-r--r--. 1 root root 15:29/root/oldgirl.txt

6.20 Summary:
1.head+tail
2.sed
3.awk

6.21 Summary:
1. Simple commands
2.find +|xargs
3. Three Musketeers grep sed (filter fetch line) awk take the line sed replace

6.22 Preview:
1.sed replacement
2. Setting aliases
Linux Basic optimization:
1. Add Users
2. Robbery color (iptables selinux) off
3. How to modify the system's character set

The Three Musketeers and common commands of Linux