Shell Learning Notes Collation (ii)

Special characters:
#！ Sign of the beginning
; Delimiters with multiple commands together
[Email protected] log]# echo A;echo b;echo C
A
B
C
. Multiple functions:
1. Equivalent to the source command
2. As part of the file name (hide filename) (use ls-a to view hidden files under Linux)
3. If you are a directory name, a single point represents the current working directory, and two points represent the previous level of the directory.
Typically used for replication when using $ cp/usr/local/mysql/*.
4. Match any single character when matching characters
\ is called an escape character. A reference mechanism for single-character.
/file name delimiter such as (/usr/local/mysql)
"(The key below the ESC key) is used to reference the command. General usage: ' Command ' takes the result as a parameter.
> >> |
Overwrite (redirect) append (redirect) pipe character (front input as output of polygon)

Control characters: (for CRT (Connection terminal))
CTRL + L Clear Screen
Ctrl + U Delete the cursor to the beginning of the character
CTRL + K deletes the character at the end of the line at the cursor position
CTRL + C (break ends a foreground job)
CTRL + D (and exit would like to. Log out of one)
CTRL + M (carriage return)
CTRL + S (hangs. Freeze stdin in one terminal)
CTRL + Q (restore. Restore stdin in one terminal
CTRL + Z (Pause operation)
CTRL + A (cursor moves to the beginning of the line)
CTRL + E (cursor moves to end of line)
Variables and parameters
Examples of the difference between single quotation marks and double quotes $:
[[email protected] ~]# hello= "A B C D"
[Email protected] ~]# echo $hello
A B C D
[Email protected] ~]# echo "$hello"
A B C D
[Email protected] ~]# echo ' $hello '
$hello
Regular Expressions:
The grep command is a powerful text search tool that uses regular expressions to search for text and to print matching rows.
Format:
grep [Options] [mode] [file]
Case text:
[Email protected] ~]# more test1
Test ABC Iiveylinux
Iivey Wwwixdbanetiiveylinux
Iivey Ydlinux
Iivey Sdglinux
Csdnwwk
Rrrrr

IXDBA Best Job
Iiiivey Test
Myshell is OK
YYYY 1998
Myshell is OK
Common usage:
If you search for a word like iivey, the whole line is displayed.
[Email protected] ~]# grep iivey test1
Test ABC Iiveylinux
Iivey Wwwixdbanetiiveylinux
Iivey Ydlinux
Iivey Sdglinux
Iiiivey Test
The-w option is a comparison of matching words the difference between the-W parameter added
[Email protected] ~]# grep-w Iivey test1
Iivey Wwwixdbanetiiveylinux
Iivey Ydlinux
Iivey Sdglinux
It is obvious that the Iiiivey test does not match and is not shown.
The-v option is to reverse the selection, which is to take out something you don't like. Generally used for configuration file filtering remove blank lines and # or;
[Email protected] ~]# grep-v Iivey test1
Csdnwwk
Rrrrr

IXDBA Best Job
YYYY 1998
Myshell is OK
The-e option initiates the effect of the extended regular. GREP-E equivalent to Egrep
$ grep-ve "^$|#"
$ egrep-v "^$|#"
--color=auto This long option is to add color to the content of the matching pattern, for easy viewing
The-O option outputs only the parts that match
[Email protected] ~]# grep-o yyyy test1--color=auto
yyyy
-C Option Statistics The total number of rows to match
[Email protected] ~]# grep-c Iivey test1
5
[Email protected] ~]# grep iivey test1
Test ABC Iiveylinux
Iivey Wwwixdbanetiiveylinux
Iivey Ydlinux
Iivey Sdglinux
Iiiivey Test
-N Displays the line number that matches to
[Email protected] ~]# grep-n iivey test1--color=auto
1:test ABC Iiveylinux
2:iivey Wwwixdbanetiiveylinux
3:iivey Ydlinux
4:iivey Sdglinux
9:iiiivey Test
-B prints the number of digits matched to the character offset (the shell starts at 0 bits) and is generally used with the-o option
[Email protected] ~]# grep-b ABC test1
0:test ABC Iiveylinux
[Email protected] ~]# grep-b-o ABC test1
5:abc
-R recursively searches for text in a multilevel directory. (. Representative of the current level directory)
[[email protected] ~]# grep iivey. -rn--color=auto
./test1:1:test ABC Iiveylinux
./test1:2:iivey Wwwixdbanetiiveylinux
./test1:3:iivey Ydlinux
./test1:4:iivey Sdglinux
./test1:9:iiiivey Test
-I ignores case
[Email protected] ~]# grep-i Myshell test1--color=auto
Myshell is OK
Myshell is OK
-e Multiple matching styles
[Email protected] ~]# grep-i-E "Myshell"-E "Iivey"-N test1--color=auto
1:test ABC Iiveylinux
2:iivey Wwwixdbanetiiveylinux
3:iivey Ydlinux
4:iivey Sdglinux
9:iiiivey Test
10:myshell is OK
12:myshell is OK
-A num matches the contents of a specified number of rows after a result
-B num matches the contents of a specified number of rows before a result
-C num matches the contents of a specified number of rows before and after a result

[[email protected] ~]# grep myshell-n-A 2 test1
10:myshell is OK
11-YYYY 1998
12-myshell is OK
[[email protected] ~]# grep myshell-n-B 2 test1
8-IXDBA Best Job
9-iiiivey Test
10:myshell is OK
[[email protected] ~]# grep myshell-n-C 2 test1--color=auto
8-IXDBA Best Job
9-iiiivey Test
10:myshell is OK
11-YYYY 1998
12-myshell is OK
If more than one match result will use "--" as a delimiter
[[email protected] ~]# grep iivey-a 1 test1--color=auto
Test ABC Iiveylinux
Iivey Wwwixdbanetiiveylinux
Iivey Ydlinux
Iivey Sdglinux
Csdnwwk
--
Iiiivey Test
Myshell is OK

This article is from the "Shong Linux Tour" blog, make sure to keep this source http://12042068.blog.51cto.com/12032068/1908032

Shell Learning Notes Collation (ii)