Shell Scripting Learning

Stream Editor

Simple usage of SED

sed[options] sed cmds files

Option –e Connect multiple Edit commands

-f Specifies the SED script file name

-N prevents input lines from being entered automatically

Sed ' 4, $d ' test.in the first 4 lines of the output test.in file

Sed ' 3q ' test.in exit before 3 lines output

Sed ' s/public/public ' test.in replace the public word in the file with uppercase

How to locate addresses in Sed_cmd

N	Represents the nth row
$	Represents the last line
M,n	Represents rows from M to n
/pattern/	Queries the rows that contain the specified pattern, such as/disk/,/[a-z]/
/pattern/, N	Represents rows from pattern matching to nth row
n,/pattern/	Represents rows from nth to rows that contain a specified pattern match
/mode 1/,/mode 2/	Represents a row from the containing pattern 1 to the containing pattern 2
!	Reverse selection, indicating m,n! , then take the opposite result of m,n

Sed–n ' 3,5 ' test.in//Print line 3rd to 5th

Sed–n '/hello/p ' test.in//print out lines containing hello

Sed–n '/hello/= ' test.in//print out line numbers with Hello

Sed–n '/hello/d ' test.in//delete the line containing Hello

Sed Common editing commands

The SED replace command uses the format

"Address" s/old word/new word/"GPW"

Address: If omitted, indicates that all rows are edited

G: Global substitution, default means replacing only the first word to match

P: Print the modified line

W fname: Writes the replaced line contents to the specified file

Sed–n ' S/NORTH/NORTH/GP ' test.in

Sed–n ' s/north/north/w data ' test.in

Sed ' s/[0-9][0-9]$/&.5/' datafile

-n means blocking automatic output

Shell Scripting Learning