SED
is a streamline editor screen-oriented utility. The sed stream editor is a text editor that performs editing
operations on information coming from standard input or a file. The stream
editor is ideally suited to performing repetitive edits that would take
considerable time if done manually. Sed edits line by line; it reads the next line of the file and
repeats the process until it is finished with the file.
Syntax
sed options 'command' filename
Let us use below test.txt file for our
sed examples.
This is a test file to learn sed command.
SED is a streamline editor.
We will learn usage of sed command with various
examples.
This is a test file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a test file to learn sed
command.
Print mth line from the file.
Syntax
sed -n np filename
Example
sed -n 2p test.txt
Output
SED is a streamline editor.
Print certain range (n1 to n2) of lines from the file.
Syntax
sed -n 'n1,n2p' filename
Example
sed -n '2,4p' test.txt
Output
SED is a streamline editor.
We will learn usage of sed command with various
examples.
This is a test file to learn sed
command.
Print every nth line starting with the specific mth line
Syntax
sed -n 'm~np' filename
testnew.txt file
This is a test file to learn sed
command.
SED is a streamline editor.
We will learn usage of sed command with various
examples.
This is a test file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a test file to learn sed
command.
This line is added to understand
current example.
Example
sed -n '2~3p' testnew.txt
Output
SED is a streamline editor.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
This line is added to understand
current example.
Print only specific lines from file.
We need to use execute option for this
purpose as shown below to display 2nd and 5th line.
Syntax
sed -n -e 2p -e 5p test.txt
Output
SED is a streamline editor.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Print line from the file containing specific pattern.
Syntax
sed -n '/pattern/p' filename
Example
sed -n '/edit/p' test.txt
Output
SED is a streamline editor.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
Print line from the file starting with number.
sed -n '/^[0-9]/p' filename
Print line from the file containing consecutive 4 numbers.
sed '/[0-9]\{4\}/p' file.txt
Print line from the file with specific string in uppercase.
Syntax
sed -n 's/lowercasestring/\U&p' filename
Example
sed -n 's/test/\U&p' test.txt
Output
This is a TEST file to learn sed
command.
This is a TEST file to learn sed
command.
This is a TEST file to learn sed
command.
Use L instead of U for lowercase.
Display particular paragraph from the file
Syntax
sed -n '/startofpara/,/endofpara/p' filename
testfile.txt
This is a test file race
You are so fantastic barry.
Run barry Run.
All the great things happens from small
begining.
Super dancer go to dance floor.
Have a rocking performance.
Example
sed -n '/This/,/Run/p' testfile
Output
This is a test file race
You are so fantastic barry.
Run barry Run.
Print lines from particular line number to specific string from the file
Syntax
sed -n 'num,/string/p' filename
Example
sed -n '1,/fantastic/p' testfile
Output
This is a test file race
You are so fantastic barry.
Display the file excluding nth line from the file.
Syntax
sed nd filename
Example
sed 2d test.txt
Output
This is a test file to learn sed
command.
We will learn usage of sed command with various
examples.
This is a test file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a test file to learn sed
command.
Display the file excluding last line from the file.
Syntax
sed '$d' filename
Example
sed '$d' test.txt
Output
This is a test file to learn sed
command.
SED is a streamline editor.
We will learn usage of sed command
with various examples.
This is a test file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
Display the file excluding certain range(n1 to n2) of lines.
Syntax
sed 'n1,n2d' filename
Example
sed '2,4d' test.txt
Output
This is a test file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a test file to learn sed
command.
Replacing a string with another string
Syntax
sed s/stringtoreplace/newstring/ filename
Example
sed s/test/dummy/ test.txt
Output
This is a dummy file to learn sed
command.
SED is a streamline editor.
We will learn usage of sed command
with various examples.
This is a dummy file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a dummy file to learn sed
command.
Replacing multiple strings with another string in the entire file at the
same time
Syntax
sed 's/stringtoreplace/newstring/;s/stringtoreplace/newstring/'
file
Example
sed 's/test/dummy/;s/usage/operations/' test.txt
Output
This is a dummy file to learn sed
command.
SED is a streamline editor.
We will learn operations of sed command
with various examples.
This is a dummy file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a dummy file to learn sed
command.
Replacing a string with other string in the file for specific line
Syntax
sed 'n s/existingstring/newstring/' filename
Example
sed '4 s/test/dummy/' test.txt
Output
This is a test file to learn sed
command.
SED is a streamline editor.
We will learn usage of sed command
with various examples.
This is a dummy file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a test file to learn sed
command.
Replacing a string with other string in the file except specific line
Syntax
sed '!n s/existingstring/newstring/' filename
Example
sed '!4 s/test/dummy/' test.txt
Output
This is a dummy file to learn sed
command.
SED is a streamline editor.
We will learn operations of sed command
with various examples.
This is a test file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a dummy file to learn sed
command.
We can also use range instead of
number if required.
sed 'n1,n2 s/existingstring/newstring/'
filename
Replacing a string with another string in the file for the lines if
specific string found
Syntax
sed '/specificstring s/stringtoreplace/newstring/' filename
Replacing a string with another string in the file for all the lines
except specific string found.
Syntax
sed '/specificstring/!s/stringtoreplace/newstring/' filename
Example
sed '/sed s/usage/operation/' filename
Output
This is a test file to learn sed
command.
SED is a streamline editor.
We will learn operation of sed command
with various examples.
This is a test file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a test file to learn sed
command.
Inserting BLANK lines in file
Syntax
sed G filename
Example
sed G test.txt
Output
This is a test file to learn sed
command.
SED is a streamline editor.
We will learn usage of sed command with various
examples.
This is a test file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a test file to learn sed
command.
To insert two blank lines execute following
Syntax
sed 'G:G' filename
In place editing of the file and performing sed operations on nth
occurrence of matched string in the line
Syntax
sed -i 's/replacestring/newstring/n' test.txt
Below example will modify the
test.txt file.
sed -i 's/test/dummy/gi' test.txt
g - global replace i.e. replace every
instance of occurence of string in the line.
i - ignore case
Below example will modify the
test.txt file and also keep the original test.txt file with org extension.
sed -i'.org' 's/test/dummy/gi' test.txt
Executing sed commands through script
Syntax
sed -f script.sed filename
cat script.sed
s/test/dummy
Example
sed -f script.sed test.txt
Output
This is a dummy file to learn sed
command.
SED is a streamline editor.
We will learn usage of sed command with various
examples.
This is a dummy file to learn sed
command.
The sed stream editor is a text editor
that performs editing operations on information coming from standard input or a
file.
Sed edits line by line.
This is a dummy file to learn sed
command.
Alternative for head command
Syntax
sed nq filename
Example
sed 3q test.txt
Output
This is a test file to learn sed
command.
SED is a streamline editor.
We will learn usage of sed command with various
examples.
Print last line of the file also Alternative for tail-1 command.
Syntax
sed -n '$p' test.txt
Output
This is a test file to learn sed
command.
