It will provide You a Brief knowledge about sed (UNIX Tool for Non Interactive Editing)

1. UNIX - sed
Non-Interactive
Stream Editor
Presentation By
Nihar R Paital

2. Introduction
 Developer : Lee E. McMahon
 Developed during: 1973-1974
 Developed at : Bell Labs
 Category : UNIX Utility
 Supported by : All UNIX flavors
Nihar R Paital

3. For practicing the commands please create a file
test1.txt and copy the below contents into test1.txt
s
s
sprint Telecom
3sprint Telecom
sprint
we are working in sprint
IBM
0IBM
nihar,rahulk,sam,papau
We are working in IBM
6We are working in IBM
nihar:rahulk:sam:papau
nihar,rahulk,sam
We are working in IBM India
Nihar R Paital

4. It performs basic text transformation on an input
stream ( A file / input from a pipeline )
 Transformation using input file
$ sed -e ‘s/oldval/newval/g’ inputFile > outputFile
Example:
$ sed -e ‘s/mumbai/pune/g’ stud.txt > stud.txt.bak
 Transformation using a filter in a pipeline
$ generate_data | sed -e ‘s/oldval/newval/g’
Example:
$ cat stud.txt | sed -e ‘s/mumbai/pune/g’ > stud.txt.bak
Nihar R Paital

5. Main options of sed
 p - print
 d - delete
 s - substitute
Nihar R Paital

6. Below special characters have vital role using sed
Character Description
 ^ Matches the beginning of the line.
 $ Matches the end of the line.
 . Matches any single character.
 * Will match zero or more occurrences of
the previous character.
 [] Matches all the characters inside the [ ].
Nihar R Paital

7. Examples (^ Matches the beginning of the line)
$ sed '/^sprint/p' test1.txt
Will Print the lines 2 times which contain sprint as a first ward of
the line
$ sed -n '/^sprint/p' test1.txt
Will Print the lines which contain sprint as a first ward of the line
$ sed 's/^sprint/IBM INDIA/g' test1.txt
Will Substitute “IBM INDIA” in place of “sprint” if it appears at
beginning of line.
$ sed '/^sprint/d' test1.txt
Will delete all lines containing “sprint” as a first word R Paital line.
Nihar of the

8. Example ($ Matches the end of the line)
$ sed '/sprint$/p' test1.txt
Will Print the lines 2 times which contain sprint as a last ward of the
line
$ sed -n '/sprint$/p' test1.txt
Will Print the lines which contain sprint as a first ward of the line
$ sed 's/sprint$/IBM INDIA/g' test1.txt
Will Substitute “IBM INDIA” in place of “sprint” if it appears at end of
line.
$ sed '/sprint$/d' test1.txt
Will delete all lines containing “sprint” as a first word of the line.
$ sed -n '/^$/p' test1.txt
Will delete all blank lines Nihar R Paital

9. Example (. Matches any single character)
$ sed -n '/./p' test1.txt
It will print the lines which at least contains a single Character.
It can be used for ignoring all blank lines.
$ sed -n '/../p' test1.txt
It will print the lines which at least contains a single Character.
$ sed -n '/IB./p' test1.txt
It will print the lines which at least contains a single Character
after the String IB”.
Nihar R Paital

10. Example (* Will match zero or more occurrences of
the previous character)
$ sed -n '/ */p' test1.txt
It will print all lines like “cat test1.txt”
$ sed -n '/ */p' test1.txt
It will print the lines which contains at leaset 2 characters except
delimited lines.
$ sed -n '/.*,.*,.*/p' test1.txt
It will print the lines where the strings are separated by at least 3
commas(,).
$ sed -n '/.*,.*,.*/p' test1.txt | cut -d"," -f 3
It will print the 3rd filed of the lines where the strings are separated by
at least 3 commas(,).
$ sed -n '/We*/p' test1.txt Nihar R Paital
It will print all the lines where at least the string “We” is present

11. Example ([ ] Matches all the characters inside
the [ ])
$ sed -n '/[abc]/p' test1.txt
This will print all the lines which contains either a or b or c as
part of the line.
$ sed -n '/^[0-9]/p' test1.txt
This will print all the lines which contains the digit 0 to 9 as part
of line
$ sed -n '/^[^0-9]/p' test1.tx
This will print all the lines which does not contains the digit 0 to
9 as part of line
$ sed 's/[abc]/we/g' test1.txt
This will replace the string “WE” where either a or b or c is
present as part of the line. Nihar R Paital

12. Sed – Line number manipulation
1 first line
$ last line
m,n m to n line
Example:
$ sed -n '3,7p' test1.txt
It will print the lines from 3 to 7
$ sed -n 'n;n;n;p' test1.txt ( every 4th line )
It will print every 4th line of the file
Nihar R Paital

13. Nihar R Paital