Shell sed Command

About SED

Sed is an online editor that processes a single line of content at a time. When processing, the currently processed rows are stored in a temporary buffer called pattern space, followed by the SED command to process the contents of the buffer, and after processing is done, the contents of the buffer are sent to the screen. Then the next line is processed, so it repeats until the end of the file. The file content does not change unless you use redirection to store the output. SED is mainly used to automatically edit one or more files, to simplify the repeated operation of the file, to write the conversion program and so on. The GNU version of SED 3.02 is described below.

-i option: Direct Action source file, source file will be modified.

sed commands and options:

A\	Add one or more rows after the current line
C\	Replace text in the current line with new text
D	Delete Row
I\	Insert text before the current line
H	Copy the contents of the schema space to the staging buffer
H	Add the contents of the schema space to the buffer
G	Remove the contents of the staging buffer and copy it to the pattern buffer
G	Remove the contents of the staging buffer and append it to the pattern buffer
L	List non-printable characters
P	Print Line
N	Reads the next line of input and processes it from the next rather than the first command
Q	End or exit sed
R	Reading input rows from a file
!	Apply all commands to a row other than the selected row
S	Replace another string with one string

Replace flag:

G	Global substitution within a row
P	Print Line
W	Writing rows to a file
X	Swapping the contents of a staging buffer and pattern space
Y	Convert a character to another character

Examples of sed:

Print: P command

Sed '/abc/p ' file	Prints the line containing ABC in file. By default, sed prints all rows to the screen, and if a row matches the pattern, print the line again
Sed-n '/abc/p ' file	Just like above, only the default behavior of SED is removed, and only matching rows are printed

Delete: D command

Sed ' 3, $d ' file	Deletes the contents from line 3rd to the last row.
Sed ' $d ' file	Delete the contents of the last row
Sed '/abc/d '	Delete the line that contains the ABC.
Sed ' 3d ' file	Delete the contents of the third row

Replace: s command

Sed ' s/abc/def/g ' file	Replace all ABC in the line with Def, and if there is no G, replace only the first ABC in the row
Sed-n ' s/abc/def/p ' file	Print only those rows where the substitution occurred
Sed ' s/abc/&def/' file	Add Def (& to match content) behind all ABC
Sed-n ' s/abc/def/gp ' file	Replace all ABC with DEF and print the lines where the substitution occurred
Sed ' s#abc#def#g ' file	Replace all ABC with DEF, followed by the character behind S to find the string and Replace the split character between the strings, in this case try #

Specify the range of rows: comma

Sed-n '/abc/,/def/p ' file	Print mode ABC to DEF line
Sed-n ' 5/,/def/p ' file	Prints the line from line fifth to the containing Def line.
sed/abd/,/def/s/aaa/bbb/g	Modify the line between pattern ABC and mode DEF to replace AAA with Def

Multiple edits-E

Sed-e ' 1,3d '-e ' s/abc/def/g ' file

Delete 1-3 lines and replace the remaining lines of ABC with DEF

Read file: R command

Sed '/abc/r newfile ' file

Read the contents of the NewFile after the line containing ABC

Write file: w command

Sed '/abc/w newfile ' file

Write newfile on lines that contain ABC

Append: a command

Sed '/abc/a\def ' file

A new line after the line containing ABC, written to Def

insert: I command

Sed '/abc/i\def ' file

A new line before the line containing ABC, written to Def

Modify: C command

Sed '/abc/c\def ' file

Replace the line containing ABC with DEF and the old text is overwritten

Read Next line: N command

Sed '/abc/{n; s/aaa/bbb/g;} ' file

Reads the next line of lines containing ABC, replacing AAA for BBB

convert: Y command

Sed ' y/abc/abc ' file

Replace A with a, a, a, a, or a b,c with a C (regular expression metacharacters do not work)

exit: Q command

Sed '/abc/{s/aaa/bbb/; q;} ' file

Include ABC in a line, replace AAA with BBB, and then exit sed.

Staging and fetching: H Command (store pattern rows to staging buffer) and g (remove row from staging buffer and overwrite pattern buffer) g (row to remove temporary buffer) command

H and G are replication behaviors (Overrides), and H and G represent append.

Sed-e '/abc/h '-e ' $G ' file	Rows containing ABC are saved to the staging buffer by the H command, and in the second command sink, when Sed reads the last line of $, the G command reads a row from the staging buffer, appended to the pattern buffer. That is, the last line of all lines that contain ABC is copied to the end of the file.
Sed-e '/abc/{h; D;} ' -E '/def/{g;} ' file	Rows containing the ABC are moved to the line containing Def and overwritten.

Staging and interchange: H and X Commands

Sed-e '/abc/h ' -E '/def/x ' file

Lines that contain ABC are converted to def rows.

Shell sed Command