Sed stands for Stream Editor. The sed is a text processing.This is a “non-interactive” stream-oriented editor. This command dosen’t change the content of original file and it works with buffers. sed has two buffers which are called pattern buffer and hold buffer ,both are initially empty. sed reads from a file or stdin, and outputs to its stdout .
- syntax
sed [options]… [script] [file]pis a command for printing the data from the pattern buffer(space). (sites-list file here)
> sed 's/com/net/p' files/sites-list
mrcatdev.net
mrcatdev.net
google.net
google.net
memoryleaks.ir
> sed 's/com/net/'p files/sites-list
mrcatdev.net
mrcatdev.net
google.net
google.net
memoryleaks.ir-noption:
To suppress automatic printing of pattern space use -n command with sed. sed -n option will not print anything, unless an explicit request to print is found
> sed 's/com/net/'p -n files/sites-list
mrcatdev.net
google.net- print specific a line of file
# print line 2
> sed '2'p -n files/sites-list
google.com
# print line 1
> sed '1'p -n files/sites-list
mrcatdev.com
#print line 3
> sed '3'p -n files/sites-list
memoryleaks.ir
#print line 4 ( not exist )
> sed '4'p -n files/sites-list- print from a specific line with step
~(customer.txt)
# Start from line 2 step 1
> sed '2~1'p -n files/customer.txt
10248 Wilman Kala Federal Shipping
10249 Tradição Hipermercados Speedy Express
10250 Hanari Carnes United Package
10251 Victuailles en stock Speedy Express
10252 Suprêmes délices United Package
10253 Hanari Carnes United Package
10254 Chop-suey Chinese United Package
10255 Richter Supermarkt Federal Shipping
10256 Wellington Importadora United Package
10257 HILARIÓN-Abastos Federal Shipping
10258 Ernst Handel Speedy Express
10259 Centro comercial Moctezuma Federal Shipping
10260 Old World Delicatessen Speedy Express
10261 Que Delícia United Package
10262 Rattlesnake Canyon Grocery Federal Shipping
10263 Ernst Handel Federal Shipping
10264 Folk och fä HB Federal Shipping
10265 Blondel père et fils Speedy Express
10266 Wartian Herkku Federal Shipping
10267 Frankenversand Speedy Express
10268 GROSELLA-Restaurante Federal Shipping
10269 White Clover Markets Speedy Express
10270 Wartian Herkku Speedy Express
10271 Split Rail Beer & Ale United Package
# Start from line 2 step 5
> sed '2~5'p -n files/customer.txt
10248 Wilman Kala Federal Shipping
10253 Hanari Carnes United Package
10258 Ernst Handel Speedy Express
10263 Ernst Handel Federal Shipping
10268 GROSELLA-Restaurante Federal Shipping- Print from start a line to another line number.
,
# start from line 1 to line 3
> sed '1,3'p -n files/customer.txt
OrderID CustomerName ShipperName
10248 Wilman Kala Federal Shipping
10249 Tradição Hipermercados Speedy Express- Print last line
$(products.txt)
#print last line of products.txt
> sed '$'p -n files/products.txt
39 Chartreuse verte 18 1 750 cc per bottle 18- Print from a line to end of file
$p
# Note: this file has a header in line 1
> sed '36,$'p -n files/products.txt
35 Steeleye Stout 16 1 24 - 12 oz bottles 18
36 Inlagd Sill 17 8 24 - 250 g jars 19
37 Gravad lax 17 8 12 - 500 g pkgs. 26
38 Côte de Blaye 18 1 12 - 75 cl bottles 263.5
39 Chartreuse verte 18 1 750 cc per bottle 18
> sed '36,$p' -n files/products.txt
35 Steeleye Stout 16 1 24 - 12 oz bottles 18
36 Inlagd Sill 17 8 24 - 250 g jars 19
37 Gravad lax 17 8 12 - 500 g pkgs. 26
38 Côte de Blaye 18 1 12 - 75 cl bottles 263.5
39 Chartreuse verte 18 1 750 cc per bottle 18
sed '1,$p' -n files/products.txt
ProductID ProductName SupplierID CategoryID Unit Price
1 Chais 1 1 10 boxes x 20 bags 18
2 Chang 1 1 24 - 12 oz bottles 19
3 Aniseed Syrup 1 2 12 - 550 ml bottles 10
4 Chef Anton's Cajun Seasoning 2 2 48 - 6 oz jars 22
5 Chef Anton's Gumbo Mix 2 2 36 boxes 21.35
6 Grandma's Boysenberry Spread 3 2 12 - 8 oz jars 25
7 Uncle Bob's Organic Dried Pears 3 7 12 - 1 lb pkgs. 30
8 Northwoods Cranberry Sauce 3 2 12 - 12 oz jars 40
9 Mishi Kobe Niku 4 6 18 - 500 g pkgs. 97
10 Ikura 4 8 12 - 200 ml jars 31
11 Queso Cabrales 5 4 1 kg pkg. 21
12 Queso Manchego La Pastora 5 4 10 - 500 g pkgs. 38
13 Konbu 6 8 2 kg box 6
14 Tofu 6 7 40 - 100 g pkgs. 23.25
15 Genen Shouyu 6 2 24 - 250 ml bottles 15.5
16 Pavlova 7 3 32 - 500 g boxes 17.45
17 Alice Mutton 7 6 20 - 1 kg tins 39
18 Carnarvon Tigers 7 8 16 kg pkg. 62.5
19 Teatime Chocolate Biscuits 8 3 10 boxes x 12 pieces 9.2
20 Sir Rodney's Marmalade 8 3 30 gift boxes 81
21 Sir Rodney's Scones 8 3 24 pkgs. x 4 pieces 10
22 Gustaf's Knäckebröd 9 5 24 - 500 g pkgs. 21
23 Tunnbröd 9 5 12 - 250 g pkgs. 9
24 Guaraná Fantástica 10 1 12 - 355 ml cans 4.5
25 NuNuCa Nuß-Nougat-Creme 11 3 20 - 450 g glasses 14
26 Gumbär Gummibärchen 11 3 100 - 250 g bags 31.23
27 Schoggi Schokolade 11 3 100 - 100 g pieces 43.9
28 Rössle Sauerkraut 12 7 25 - 825 g cans 45.6
29 Thüringer Rostbratwurst 12 6 50 bags x 30 sausgs. 123.79
30 Nord-Ost Matjeshering 13 8 10 - 200 g glasses 25.89
31 Gorgonzola Telino 14 4 12 - 100 g pkgs 12.5
32 Mascarpone Fabioli 14 4 24 - 200 g pkgs. 32
33 Geitost 15 4 500 g 2.5
34 Sasquatch Ale 16 1 24 - 12 oz bottles 14
35 Steeleye Stout 16 1 24 - 12 oz bottles 18
36 Inlagd Sill 17 8 24 - 250 g jars 19
37 Gravad lax 17 8 12 - 500 g pkgs. 26
38 Côte de Blaye 18 1 12 - 75 cl bottles 263.5
39 Chartreuse verte 18 1 750 cc per bottle 18- Prints from the line matches the given pattern to end of file.
/pattern/,$p
# print from lax pattern to end of file
> sed '/lax/,$p' -n files/products.txt
37 Gravad lax 17 8 12 - 500 g pkgs. 26
38 Côte de Blaye 18 1 12 - 75 cl bottles 263.5
39 Chartreuse verte 18 1 750 cc per bottle 18
# print journalctl from date Nov 09 to end of file
journalctl | sed '/Nov 09/, $p' -n | less- Prints N next line
/pattern/Np
Print pattern and next line
> sed '/lax/,+1p' -n files/products.txt
37 Gravad lax 17 8 12 - 500 g pkgs. 26
38 Côte de Blaye 18 1 12 - 75 cl bottles 263.5The G function appends the contents of the holding area to the contents of the pattern space. The former and new contents are separated by a newline. The maximum number of addresses is two.
- Double Space with
G
> sed 'G' files/passwords.txt
root
user
admin
123456789
administrator
test- Add space except a specific line
# add space except line 2
> sed '2!G' files/passwords.txt
root
user
admin
123456789
administrator
test- Add space then print last line
> sed 'G;$p' -n files/passwords.txt
test
# there is a spaceThe h (hold) function copies the contents of the pattern space into a holding area (also called as sed hold space), destroying any previous contents of the holding area.
> cat files/passwords2.txt
Admin
petter23
0129345
abcde24
oakasw
> sed -n '/^[0-9]/h;${x;p}' files/passwords2.txt
0129345
# ^[0-9]/h => if the line started with number copy it to hold space
# x => swap pattern with hold space
#Line------Command------Pattern Space-------Hold Space
# 1 ^[0-9]/h Admin -
# 2 ^[0-9]/h petter23 -
# 3 ^[0-9]/h 0129345 0129345
# 4 ^[0-9]/h abcde24 0129345
# 5 ^[0-9]/h oakasw 0129345
# > x 0129345 oakasw
# p 0129345 oakasw- Print file content in reverse order
> sed -n '1!G;h;$p' files/passwords2.txt
oakasw
abcde24
0129345
petter23
Admin
#Line------Command------Pattern Space-------Hold Space
# 1 1!G Admin
# h Admin Admin
# p Admin Admin
# 2 1!G petter23 Admin
# Admin
# h petter23 petter23
# Admin Admin
# p petter23 petter23
# Admin Admin
# 3 1!G 0129345 petter23
# petter23 Admin
# Admin
# h 0129345 0129345
# petter23 petter23
# Admin Admin
# p 0129345 0129345
# petter23 petter23
# Admin Admin/sindicates the search and replace task.
echo "Hello Bash" | sed "s/Bash/zsh/"
# output => Hello zsh- Read file and serach and replace
> sed 's/mrcatdev/https:\/\/mrcatdev/' files/sites-list
https://mrcatdev.com
google.com
memoryleaks.irgoption is used insedcommand to replace all occurrences of matching pattern
> sed 's/com/org/g' files/sites-list
mrcatdev.org
google.org
memoryleaks.ir- Replace after the second occurrence of a match on each line by using
g2
> sed 's/com/coooom/' files/sites-list | sed 's/o/O/g2'
mrcatdev.coOOOm
goOgle.cOOOOm
memoryleaks.ir- Replace the last occurrence of a match on each line by using
\1
> sed 's/com/coooom/' files/sites-list | sed 's/\(.*\)o/\1O/'
mrcatdev.coooOm
google.coooOm
memOryleaks.ir- Replace the first match in a file by using
1
> sed '1 s/com/net/' files/sites-list
mrcatdev.net
google.com
memoryleaks.ir- Replace the last match in a file by using
$
> sed '$ s/m/M/' files/sites-list
mrcatdev.com
google.com
Memoryleaks.ir
> sed '$ s/m/M/g' files/sites-list
mrcatdev.com
google.com
MeMoryleaks.ir- Substitute text
# -e script, --expression=script | add the script to the commands to be executed
> sed -e '/Chais/ s/18/22/; /Chang/ s/19/25/;' files/products.txt | sed '1,3'p -n
ProductID ProductName SupplierID CategoryID Unit Price
1 Chais 1 1 10 boxes x 20 bags 22
2 Chang 1 1 24 - 12 oz bottles 25- Substitute text with not operator
!
# find and replace 'e' with xxxxxx except line which has 'p'
> sed -e '/p/! s/e/xxxxx/i;' files/passwords2.txt
Admin
petter23
0129345
abcdxxxxx24
oakasw- Add string before and after the matching pattern using
\1\2and …
> cat sites-list
mrcatdev.com
google.com
memoryleaks.ir
> sed 's/\(.*com\)/https:\/\/\1/g' files/sites-list
https://mrcatdev.com
https://google.com
memoryleaks.ird option is used in sed command to delete any line from the file.
> sed '/ir/d' files/sites-list
mrcatdev.com
google.com- Delete empty lines
> cat awk-tax.awk
#1 function tax(price){
#2 tx=20;
#3 return ((price * tx)/100)+price
#4 }
#5
#6 BEGIN {
#7 print "ENTER PRICE:"
#8 getline p < "-"
#9 print "Tax = " tax(p)
#10 }
> sed '/^$/d' awk-tax.awk
#1 function tax(price){
#2 tx=20;
#3 return ((price * tx)/100)+price
#4 }
#5 BEGIN {
#6 print "ENTER PRICE:"
#7 getline p < "-"
#8 print "Tax = " tax(p)
#9 }