65.shell special symbols with and Cut,sort,wc,uniq,tee,tr,split commands

Special symbols for Liunx

• Represents a number of letters or numbers
  ？ Any one character
  "#" Comment
  \ de-Semantic characters
  | Pipe character

1.* represents any arbitrary character or number

[[email protected]/]# ls *.txt
1.txt
[Email protected]/]#

2.? Any one character

[email protected]/]# ls?. txt
1.txt
[Email protected]/]#

3. Notes

[Email protected]/]# #11111
[Email protected]/]#
PS: Meaning is the explanation

4, \ de-righteousness

[[email protected]/]# ls. txt
1.txt
[[email protected]/]# ls *.txt
LS: Cannot access the. txt: no file or directory
[Email protected]/]#

5. Pipe break

[Email protected]/]# Cat/etc/passwd|grep root
Root:x:0:0:root:/root:/bin/bash
Operator:x:11:0:operator:/root:/sbin/nologin
[Email protected]/]#

Cut command Command type

File Management

Command description

Used to intercept a field to display it.

Command syntax

Cut "Parameters"

Parameters

-D,--delimiter= delimiter uses the specified delimiter instead of a tab as the area demarcation
-C, the--characters= list selects only those characters that are specified
-F: Specify a section

Case: View the/etc/passwd file to: Display the first paragraph for the separator

[[email protected]/]# cat/etc/passwd|head |cut-d ":"-F 1
Root
Bin
Daemon
cd/
Lp
Sync
Shutdown
Halt
Mail
operator
[Email protected]/]#

Sort Command Command description

This command is used to sort the document

Command syntax

sort [parameters] [file]

Parameters

-T separator: Same as cut-d
-N: Sorting with pure numbers
-R: Direction sort
-U: To repeat
-K:-kn1,n2: Sorted by N1 interval to N2 interval, can only write-kn1, sort N1 field

Case one: Without any parameters, the ASCII values are compared, and finally they are output in ascending order.

[Email protected]/]#
[Email protected]/]# Head/etc/passwd|sort
Adm:x:3:4:adm:/var/adm:/sbin/nologin
Bin:x:1:1:bin:/bin:/sbin/nologin
Daemon:x:2:2:daemon:/sbin:/sbin/nologin
Halt:x:7:0:halt:/sbin:/sbin/halt
Lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
Mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
Operator:x:11:0:operator:/root:/sbin/nologin
Root:x:0:0:root:/root:/bin/bash
Shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
Sync:x:5:0:sync:/sbin:/bin/sync
[Email protected]/]#

WC Command Command description

For statistical

Command syntax

WC [parametric]

Parameters

-L: Count rows
-M: Statistics of characters
-W: Number of statistical words

Case

[Email protected]/]# cat/etc/passwd |wc-l-m-w
19 29 883
[Email protected]/]# cat/etc/passwd |WC
19 29 883
[Email protected]/]#

PS: In fact, there is no need to add parameters

UNIP Command Command description

Used to delete duplicate rows

Command syntax

Xxxxx|unip
Parameters
-C statistics Number of rows to repeat

Case

[Email protected] ~]# Uniq testb.txt
111
222
111
333
[Email protected] ~]# sort Testb.txt |uniq
111
222
333
[Email protected] ~]# sort Testb.txt |uniq-c
2 111
1 222
1 333

Tee command

Tee followed by the filename, its role is similar to redirect,, the specific gravity of a function, the file is written to the following file and displayed on the screen, usually used for pipe character |

Case

#echo "AAAAAAAAAAAAAAA" |tee testb.txt
Aaaaaaaaaaaaaaa
#cat Testb.txt
Aaaaaaaaaaaaaaa

Command TR

TR is used to replace characters, which are commonly used to handle special symbols appearing in documents, such as the symbol ^m that appear in a DOS document.
Options:

Parameters

-D means to delete a character followed by the character to be deleted.
-S means to remove duplicate characters.
Turn lowercase letters into uppercase letters, such as TR ' [A-z] ' [A-z] ':

Case

#head –n2/etc/passwd |tr ' [A-z] ' [A-z] '
Root:x:o:o:root:/root:/bin/bash
Bin:x:11:bin:/bin:/sbin/nologin
You can also replace one character:
#grep ' root '/etc/passwd |tr ' r ' R '
Root:x:o:o:root:/root:/bin/bash
Operator:x:11:0:operator:/root:/sbin/nologin

Command Split command description

Split is used for cutting documents, and the common options are-B and-L.

Parameters

-B means that the document is split by size in bytes
-L to divide the document by the number of rows

Case

#split –b passwd
#ls
passwd xaa xab xac xad xae

Shell some other special symbols 1, special symbols $

$ can be used as an identifier in front of a variable, and you can! Used in combination.

#cd:
#ls Testb.txt
Testb.txt
#ls!$
LS Testb.txt
Testb.txt
!$ represents the last variable of the previous command, and in this case the last command is Testb.txt, then entering!$ under the current command represents Testb.txt.

2, special symbols;

To run two or more two commands in a single line of commands, you need to add a symbol between the commands.

#mkdir Testb.txt; Touch Test1.txt; Touch Test2.txt; Ls–d test* Creating directories, creating files, listing directories

3. Special Symbols ~

The symbol ~ Represents the user's home directory, the root user's home directory is/root, the normal user's home directory is/home/username.

4. Special Symbols &

If you put a command in the background, you need to add the symbolic &, which is usually used for long commands. For example, it can be used after sleep, as shown below:

#sleep &
[1]3008
#jobs
[1]+ Running in Sleep &

5. REDIRECT Symbols >, >>, 2> and 2>>

and >> the meaning of substitution and append respectively. When we run a command error, the error message is output to the current screen. If you want to redirect to a text, use the redirect symbol 2> or 2>>, which represent error redirection and error append redirection, respectively.
#ls AAAA
LS: Unable to access AAAA: No file or directory
#ls AAAA 2>/tmp/error
#cat/tmp/error
LS: Unable to access AAAA: No file or directory
#ls AAAA 2>>/tmp/error
#cat/tmp/error
LS: Unable to access AAAA: No file or directory
LS: Unable to access AAAA: No file or directory

6. Brackets []

The combination of characters in brackets, representing any of the character combinations, can also represent a range (1-3,a-z).

#cd/TMP/10
#ls –d test*
Test1.txt test2.txt Testb.txt TestDir
#ls –d Test[1-3].txt
Test1.txt Test2.txt
#ls –d Test[12b].txt
Test1.txt Test2.txt Testb.txt
#ls –d Test[1-9].txt
Test1.txt Test2.txt
#ls –d Test[1-9a-z].txt
Test1.txt Test2.txt Testb.txt

7. Special Symbols && | |

A semicolon has just been mentioned above for the delimiter between multiple commands. There are also two special symbols that can be used in the middle of multiple commands, that is, "&&" and "| |" are all listed below:

Command1; Command2
Command1 && Command2
Command1 | | Command2
When using ";", Command2 will be executed regardless of whether Command1 is executed successfully;
When using "&&", only if the Command1 is executed successfully, Command2 will execute, otherwise command2 not execute;
When using "| |", the Command1 execution succeeds Command2 not execute, otherwise go to execute Command2, in short Command1 and Command2 always have a command to execute.

65.shell special symbols with and Cut,sort,wc,uniq,tee,tr,split commands