Discussion on the use of sed and awk commands in linux

This paper mainly studies the use of sed and awk commands in linux, as follows.

sed command: No redirection will actually change the content in the source file

The query

1) sed - n '/ sbin p' passwd

Means to query and print out all the lines in the passwd file containing the sbin character, two of which/represent the regular expression. -n and /p are parameters of the command and need to be used together

(2) sed - n 'xp' passwd

x is a number that prints out the x line in the passwd file

The new statement

This is added after line 1 'passwd'

Where a means add content, the number 1 means line 1, and the statement above means add content after line 1 of the passwd file

sed '1i this is the data inserted before line 1' passwd

Where i stands for insert data, the number 1 stands for line 1, and the statement above means insert text before line 1

3. sed '1c hello world' passwd

c represents substitution, and the statement means that the first line in the password file is replaced with hello world

4, sed 's/false/true/' passwd

Replaces the false character in the passwd file with the true character

Delete statements

1) sed '/ postgres d' passwd

Delete all lines in the passwd file where the regular expression matches postgres

2, sed '2d' passwd

Delete line 2 of the passwd file

conclusion

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