Use of the sed command, sed

Use of the sed command, sed

Sed streaming Editor/text filtering

Stream Editor

Based onPattern MatchingFilter/Modify text

Syntax format:

Sed 'edit directive 'file 1 file 2

All contents before and after modification are output.

Sed-n 'edit directive 'file 1 file 2

Only the modified and filtered content is displayed.

Sed-I 'edit directive 'file 1 file 2

The modified content will be replaced directly without output.

Edit command writing

Format: [address 1 [, address 2] operation type

SemicolonSeparate

Sed-n '3 P; 5 p '/etc/hosts

The most common operation type

P output/print text lines

N remove a line of text (skip the current line)

D. Delete

S string replacement

A. append new text

Output text content by line

Sed-n 'P; n' file.txt outputs all odd rows

Sed-n'n'; P' file.txt outputs all even rows

Use Regular Expressions

Sed-n'/w2k8/, $ P' file.txt

Sed-n'/\ <This> \/P' file.txt \ <word> \ indicates matching a word

Delete a qualified row

Sed '2, 3d 'file.txt Delete 2-3 rows

Sed '/w2k8/d; $ d' file.txt Delete the row and last row containing w2k8

Delete rows that do not meet the conditions

Sed/2, 3! D/file.txt delete other rows except 2-3

Replace qualified text

Sed '3, 4S/yes/no/G' file.txt replace all yes in 3-4 rows with no

Special effects of replacement

Sed '1, 2 s/^/#/G' file.txt is inserted at the beginning of line 1-2 # (usually batch comment)

Sed's/yes // G' file.txt delete all yes in file.txt (replaced with null)