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Various poses for text modification using sed

2022-06-11 18:14:00 【wx61eaae213a986】

SED Introduce

sed（Stream Editor） Stream editor , yes Unix Common command line programs . yes Bell Laboratory, Lee E.McMahon stay 1973 Year to 1974 The development was completed in two years , Currently, it can be used in most operating systems .

sed The emergence of the game is as grep A successor to , because grep It can only be found and replaced simply , But there may be various needs such as deletion ,McMahon Developed a more versatile tool .sed Well known grammatical rules include the use of / Pattern matching , as well as s/// To replace . Tools that exist at the same time ed Together ,sed The grammar of English influenced the later development of ECMAScript and Perl.GNU sed Added a lot of features , Including famous in-place editing.

grammar

to glance at sed Basic syntax ：

       
        sed [-nefri] 'command' [file ...]
        
sed '{[/]<n>|<string>|<regex>[/]}d' <fileName>
        
sed '{[/]<adr1>[,<adr2>][/]d' <fileName>
       
       
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The sed utility reads the specified files, or the standard input if no files are specified, modifying the input as specified by a list of commands. The input is then written to the standard output.

sed Get content from file or standard input , Then modify the contents according to the command list , Finally, send the results to the standard output .

The meaning of some common options ：

-n Use silence (silent) Pattern . In general sed In the use of , All from STDIN The information about is usually listed on the screen . But if you add -n After the parameter , Only through sed The line of special treatment ( Or action ) To be listed .
-e Directly in command line mode sed Action editor .
-f Direct will sed The action is written in a file , adopt -f Parameters execute actions in the file .
-i Directly modify the contents of the read file , Instead of printing to standard output .

Some common commands ：

a newly added
d Delete
s Replace
p Print

Delete the contents of the file

adopt d Parameters plus matching rules , We can easily delete the contents of the file .

       
        $ sed '3d' fileName.txt   # Delete the first 3 That's ok , And print the modification to the standard output 
        
$ sed -i '3d' fileName.txt # Delete the first 3 That's ok , And take effect in the document , The following command will not add this parameter 
        

        
#  Delete last line 
        
$ sed '$d' fileName.txt
        

        
#  Delete 7-9 That's ok 
        
$ sed '7,9d' fileName.txt
        

        
#  Delete all blank lines 
        
$ sed '/^$/d' fileName.txt 
        
$ sed '/./!d' fileName.txt
        

        
#  Delete the line that matches the string 
        
$ sed '/awk/d' fileName.txt 
        

        
#  Delete all rows between two matches 
        
$ sed '/patternA/,/patternB/d' fileName.txt
        

        
#  Delete the matching row to  n(5)  Between lines , In the same way, it can be reversed , Delete the content from a row to the matching row 
        
$ sed '/pattern/,5d' fileName.txt
        

        
#  Delete rows that meet multiple criteria 
        
$ sed '/patternA/d;/patternB/d' fileName.txt
       
       
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Replace the contents of the file

If you just want to modify part of a line , have access to g Parameters , Specific examples are as follows .

       
        $ sed 's/^/ABC /' fileName.txt # Add in each line ABC
        

        
$ sed 's/patternA/String/' fileName.txt # Replace the matching content with the specified string 
       
       
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Although the container 、 Cloud infrastructure is very common today , In the enterprise operation and maintenance scenario, we directly use sed The chances of command are diminishing . but sed It's like a secret weapon in individual combat , If we can master , We will be able to keep our hands on food and not panic , Take this opportunity to show your boss , Then your future will be greatly improved .