Sed is a good file processing tool, itself is a pipe command, mainly in the behavior of the unit processing, you can replace the data rows, delete, add, select and other specific work, the following first understand the use of SED
The SED command line format is:
sed [-nefri] ' command ' input text
Common options:
- N: Use Quiet (silent) mode. In the usage of general sed, all data from stdin is generally listed on the screen. However, if you add the-n parameter, only the line (or action) that is specially processed by SED is listed.
-E: The Action of SED is edited directly on the instruction list mode;
-F: The action of SED is written directly in a file, and-f filename can perform the SED action within filename;
-r:sed's actions support the syntax of extended formal notation. (Presupposition is the basic formal notation of French law)
-I: Directly modify the contents of the read file instead of the screen output.
common commands:
a : New, a can be followed by a string, and these strings will appear on a new line (the current next line) ~
c : Replace, C can be followed by string, these strings can replace the line between N1,N2!
d : Delete, because it is deleted, so D usually does not take any of the following;
i : Insert, I can be followed by a string, and these strings will appear on a new line (the current line);
p : Print, that is, a selection of information printed. Normally p works with parameter Sed-n ~
s : Replace, can be directly replaced by work! Usually this s action can be paired with formal notation! For example 1,20s/old/new/g is!
example: (Suppose we have a file named ab)
Delete a row
[[email protected] Ruby [[email protected] ruby] # sed ' $d ' ab #删除最后一行
[[email protected] Ruby ] # sed ' 1,2d ' ab # Delete the first row to the second row
[[email protected] ruby] # sed ' 2, $d ' AB #删除第二行到最后一行
Show a line
. [[email protected] Ruby ] # sed-n ' 1p ' ab # Display the first line
[[email protected] ruby] # sed-n ' $p ' ab& nbsp; #显示最后一行
[[email Protected] Ruby] # sed-n ' 1,2p ' ab # Show first row to second row
[[email protected] ruby] # sed-n ' 2, $p ' ab& nbsp; #显示第二行到最后一行
Querying using a pattern
[[email protected] ruby] # sed-n '/ruby/p ' ab #查询包括关键字ruby所在所有行
[[email protected] ruby] # sed-n '/\$/p ' AB #查询包括关键字 $ where all lines, using backslashes \ Shielding special meaning
Add one or more lines of string
[email protected] ruby]# Cat AB
Hello!
Ruby is me,welcome to my blog.
End
[[email protected] ruby]# sed ' 1a drink tea ' ab#第一行后增加字符串 "Drink Tea"
Hello!
Drink tea
Ruby is me,welcome to my blog.
End
[[email protected] ruby]# sed ' 1,3a drink tea ' ab #第一行到第三行后增加字符串 "Drink Tea"
hello!
drink Tea
Ruby is me,welcome to my blog.
drink Tea
end
drink Tea
[[email protected] ruby] # sed ' 1a drink tea\nor Coffee ' ab #第一行后增加多行, use line break \ n
hello!
drink Tea
or coffee
Ruby is Me , Welcome to my blog.
End
Instead of one or more lines
[[email protected] ruby] # sed ' 1c Hi ' ab& nbsp; #第一行代替为Hi
Hi
Ruby is Me, Welcome to my blog.
End
[[email protected] Ruby] # sed ' 1,2c Hi ' ab #第一行到第二行代替为Hi
Hi
End
Replace part of a line
format: sed "s/the string to replace /new string /g ' (the string to be replaced can be used with regular expressions)
[[email protected] Ruby] # sed-n '/ruby/p ' ab | Sed ' s/ruby/bird/g ' #替换ruby为bird
[[email protected] ruby] # sed-n '/ruby/p ' ab | Sed ' s/ruby//g ' #删除ruby
Insert
[[email protected] ruby] # sed-i ' $a bye ' ab #在文件ab中最后一行直接输入 "Bye"
[email protected] ruby]# Cat AB
Hello!
Ruby is me,welcome to my blog.
End
Bye
"Shell" sed command