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P Print Mode space content

d Delete Mode space content

A appends a row

I insert a row

C Replace Line

! Non -

N reads a row, overwriting the schema space content

For example echo-e ' 1\n2\n3\n4 ' |sed ' n;s/\n//'

The first line is read first, when the mode space is 1$

Then executes the n command, after the output mode space, reads the next line, this time the mode space is 2$, then executes after the s/\n//

The next line is then read in, and the mode space is 3$

。。。

N reads a row and appends to the pattern space

For example echo-e ' 1\n2\n3\n4 ' |sed ' n;s/\n//'

The first line is read first, when the mode space is 1$

Then executes the n command, appending to the pattern space, where the mode space is 1\n2

Then execute the s/\n//command, delete \ n, and output the schema space content 12

Next, continue reading to the next line, when the mode space is 3$

。。。

P Print Mode space content

For example echo-e ' 1\n2\n3\n4 ' |sed '/2/p '

First read the first line, when the mode space is 1$, does not match

Then read into the second line, where the pattern space is 2$, matching the Execute P command

。。。

Note: Since SED executes line by row, the mode output mode space content, so when the match executes P, the match line prints two times

P Print mode space first row

Give an example echo-e ' 1\n2\n3\n4 ' |. /sedsed-d--hide=hold ' N; P

First read into the first row, the mode space is 1$, then execute the n command, read the next line and append to the pattern space, the mode space is 1\n2, and then execute the P command print mode space the first line is \ n front of the content

Then pattern output mode space

Next, continue reading to the next line, when the mode space is 3$

。。。

d Delete Mode space content

Give an example echo-e ' 1\n2\n3\n4 ' |. /sedsed-d--hide=hold '/2/d '

First read into the first line, when the mode space is 1$, does not match the automatic output

Read the second line again, this time the mode space is 2$, match, execute D command, empty the mode space

Then read into the next line, where the mode space is 3$

。。。

Note D will not pass to standard output after execution, and will discard subsequent commands to read new content

D Delete the first line of the pattern space

Give an example echo-e ' 1\n2\n3\n4 ' |. /sedsed-d--hide=hold ' n;d '

First read into the first line, when the mode space is 1$, the execution of the n command, the mode space is 1\n2, and then execute the d command, delete the first line after the 2$, do not pass the standard output, discard the following command to read the next line

Read in the next line, this time the mode space is 2\n3 ...

H overwrites content in the current mode space to hold space

H appends the contents of the current pattern space to the hold space

G Overwrite content in current hold space to pattern space

G Append the contents of the current hold space to the mode space

x swaps the current space and schema space content

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1. Delete empty lines

General situation sed '/^$/d ' file

Special case, Existence tab and other tabs sed '/^\s*$/d ' file

\s for tab \ r \ n Spaces

2. Print line numbers

Sed-n '/if/= ' file

Prints the line number of the line that matches if

Sed-n ' $= ' file

Total number of lines printed file

3. Multi-line command

N reads the next line into the pattern space, inserts the line below the current row in the pattern space and divides it by \ n, and then reads the schema space content before it is read into the schema space instead of the previous content

D Delete the first line of the mode space, the first action \ n before the content; D is to delete the schema space so the content

P The first line of the print mode space, the content before the first action, and P is the print mode space so the content

Note, the Print command is typically used after next, before the delete

H Copy the contents of the pattern space to the hold space, and the space of the pattern space, and H appends the schema spatial content to the hold space, and adds a newline character after the original hold space.

G will keep the contents of the space copied to the pattern space, covering the mode space, G will keep the space content appended to the pattern space, after the original mode space to add a newline character

X-swap mode space and preserve space content

4. Tags

b tag, unconditional jump

Sed '/lable/ba;s/lable/lable/;:a;s/$/\!/' file

If match lable jumps to label a

Mismatch lable is executed from left to right

T tag, conditional jump

Sed '/lable/s/lable/lable/;t;s/$/\!/' file

If the match executes, the match is followed by the substitution

Do not match jump to the T tag, perform the subsequent substitution

This article is from the "Eight Miles" blog, so be sure to keep this source http://5921271.blog.51cto.com/5911271/1749156

Sed common knowledge points