Shulou(Shulou.com)06/01 Report--

Today, I will talk to you about the basic usage of sed, which may not be well understood by many people. in order to make you understand better, the editor has summarized the following for you. I hope you can get something from this article.

Sed contains several functions, the most common of which is the replace command

1 replacement

S/pattern/replacement/flags

Flags includes the following

A number between 1-512 to replace the nth match.

G: globally modify all matches

P: all content in print mode

W:file to write the schema contents to the file file

For replacement, the following characters have a special meaning

&: replace it with pattern

\ n: match the nth string, specified with "\ (" and "\)" in pattern

\: escape character

& replaced by pattern, but\ & escaped

[oracle@ ~] $cat test

ORA

[oracle@ ~] $cat test | sed's Associates ORA Reilly\ & Associates, Inc./g'

O'Reilly & Associates, Inc.

[oracle@ ~] $cat test | sed's Associates ORA Reilly, Inc./g'

O'Reilly ORA Associates, Inc.

[oracle@ ~] $cat test1

See Section 19.40 See Section 18.89

See Section 19.09

See Section 07.10

[oracle@ ~] $sed 's/See Section [1-9] [0-9] *\. [1-9] [0-9] * / (&) / 2' test1-enclose "()" for the second matching character of each line

See Section 19.40 (See Section 18.89)

See Section 19.09

See Section 07.10

Replace the second See of each line with a newline character

[oracle@] $sed 's/See/\\ nUniverse 2' test1-- it doesn't work

See Section 19.40\ nSection 18.89

See Section 19.09

See Section 07.10

[oracle@ ~] $sed 's/See/\

> / 2' test1-the line breaks successfully, but it is not easy to maintain

See Section 19.40

Section 18.89

See Section 19.09

See Section 07.10

[oracle@ ~] $sed 's/See/\ nAccord 2' test1-use\ nsubstitute

See Section 19.40

Section 18.89

See Section 19.09

See Section 07.10

Search for the second matching pattern in each line and swap its first / second element

[oracle@] $sed's /\ (See Section\)\ ([1-9] [0-9]\. [1-9] [0-9]\) /\ 2\ 1Universe 2' test1

See Section 19.40 18.89 See Section

See Section 19.09

See Section 07.10

[oracle@ ~] $sed'/ 0 [1-9]\. / s /\ (See Section\)\ ([0-9] [0-9] *. [1-9] [0-9]\) / 2\ 1 A test1-first search contains "0 [1-9]." If it satisfies the matching pattern, its first / second element is swapped

See Section 19.40 See Section 18.89

See Section 19.09

07.10 See Section

[oracle@ ~] $cat test1 | grep UNIX

UNIX

[oracle@ ~] $sed 's/UNIX/\\ s Murray 1 &\\ s 0 UNIX' test1-use & replace the previous UNIX

\ s-1UNIX\ s0

[oracle@ ~] $sed 's/UNIX/\ s test1-use\ & make it a normal character, change\ s to\ s, and s is not a special character, so\ s equals s

Smuri 1 &\ s 0

[oracle@ ~] $sed 's/UNIX/s-1\ &\\ s0Universe' test1

Smuri 1 &\ s 0

Ignore case

[oracle@ ~] $cat test5

Who finger w last

[oracle@ ~] $sed's test5

Who www w last

2 Delete (d)

Delete the row if the row matches

/ ^ $/ d-Delete blank lines

[oracle@ ~] $cat test3

Adf

Sdf

[oracle@ ~] $sed'/ ^ $/ d'test3-- Delete blank lines

Adf

Sdf

[oracle@ ~] $sed'/. /! d 'test3-Delete blank lines,! Denotes notrecover.Compact! That is, lines without characters

Adf

Sdf

[oracle@ ~] $sed'/. / d' test3-Delete non-blank lines

[oracle@ ~] $sed'$d' test3-- Delete the last line

Adf

[oracle@ ~] $sed '2d' test3-Delete line 2

Adf

Sdf

[oracle@ ~] $sed'$! d 'test3-keep only the last row of data and delete the rest

Sdf

3 append (a) / insert (I) / change (c)

The format is as follows

[line-address] [a | I | c] text

Note: (O'Reilly) indicates that "these commands must be specified on multiple lines, (\ for escaping the end of the line)"

[line-address] [a | I | c]\

Text

But personal experiments have found that there is no need for so much trouble.

[oracle@ ~] $cat test3

Adf

Sdf

Add information before and after the first and last lines, respectively

[oracle@] $sed-e'1i insert before the first line'-e' $an append after the last line' test3

Insert before the first line

Adf

Sdf

Append after the last line

Using the change (c) command is sometimes more efficient than replacing, as follows:

Replace the input parameters for all lines starting with ".sp" with 5

[oracle@ ~] $cat test4

.sp 1.5

.sp 4

.sp

5.sp 67

[oracle@ ~] $sed'/ ^\ .sp/c\ .sp 5' test4-search for lines that start with .sp and replace the entire line with .sp 5

.sp 5

.sp 5

.sp 5

5.sp 67

4 list (l)

Displays the contents of the mode space, displaying non-print characters as two-digit ASCII codes, similar to vi's (: l) or cat-v

Can be used to detect invisible characters

Oracle@ ~] $cat-v test5

Who finger w last ^ M

^ M

^ M

[oracle@ ~] $sed-e "l" test5

Who finger w last\ r $

Who finger w last

\ r$

\ r$

[oracle@] $sed-n-e "l" test5

Who finger w last\ r $

\ r$

\ r$

The function of-n option is as follows:-n,-- quiet,-- silent suppress automatic printing of pattern space

5 next line (n)

Output the contents of the pattern space, and then read the next line of input without returning to the top of the script

[oracle@usuwsoadb06] $cat-n test7

1 apple

2 banana

3 mango

4 orange

5 strawberry

[oracle@usuwsoadb06 ~] $sed'/ ban/ {nscape d;} 'test7-- Delete the next line that matches the pattern

Apple

Banana

Orange

Strawberry

The difference between N and n, the former outputs the current matching line

[oracle@usuwsoadb06] $sed-n'/ ban/ {n; p;} 'test7

Mango

[oracle@usuwsoadb06 ~] $sed-n'/ ban/ {N; p;} 'test7

Banana

Mango

Look for the next line that contains ban characters and replace it with justin

[oracle@usuwsoadb06 ~] $sed'/ ban/ {n; s test7.

Apple

Banana

Justin-the original mango is now justin

Orange

Strawberry

6 read and write files (rcode)

Write a file

Read eligible lines from one file and write them to another file, with the following syntax:

Sed'/ pattern/w outputfile' inputfile

[oracle@] $cat-n test7

1 apple

2 banana

3 mango

4 orange

5 strawberry

[oracle@ ~] $sed-n'2 test8' test7 4w test8' test7-enter 2-4 lines of test7 into test8

[oracle@ ~] $cat test8

Banana

Mango

Orange

[oracle@ ~] $sed-n'/ mango/,$w test8' test7-writes test7 to test8 from the data containing the mango row to the last row

[oracle@ ~] $cat test8

Mango

Orange

Strawberry

[oracle@ ~] $sed-n'$! W test8' test7-write all the contents of test7 to test8 except the last line

[oracle@ ~] $cat test8

Apple

Banana

Mango

Orange

Read the file-it doesn't actually change the contents of the file.

Sed'/ pattern/r outputfile' inputfile

-- write the contents of the file to sed output

[oracle@ ~] $cat test9

1apple

1banana

1mango

[oracle@ ~] $cat test10

2orange

2strawberry

[oracle@ ~] $sed'2 test10' test9-insert the contents of the test10 file into test9 from line 2 to the last line

1apple

1banana

2orange

2strawberry

1mango

2orange

2strawberry

[oracle@ ~] $sed'$! r test10' test9- inserts test10 into test9 after the rest of the line except the last one

1apple

2orange

2strawberry

1banana

2orange

2strawberry

1mango

After reading the above, do you have any further understanding of the basic usage of sed? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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