Bash-Beginners-Guide

Bash Guide for Beginners
sandy ~>
As you notice, sed prints the entire file, but the lines containing the search string are printed twice. This is not
what we want. In order to only print those lines matching our pattern, use the -n option:
sandy ~> sed -n '/erors/p' example
It is a text with erors.
Lots of erors.
So much erors, all these erors are making me sick.
sandy ~>
5.2.2. Deleting lines of input containing a pattern
We use the same example text file. Now we only want to see the lines not containing the search string:
sandy ~> sed '/erors/d' example
This is the first line of an example text.
This is a line not containing any errors.
This is the last line.
sandy ~>
The d command results in excluding lines from being displayed.
Matching lines starting with a given pattern and ending in a second pattern are showed like this:
sandy ~> sed -n '/^This.*errors.$/p' example
This is a line not containing any errors.
sandy ~>
Note that the last dot needs to be escaped in order to actually match. In our example the expression just
matches any character, including the last dot.
5.2.3. Ranges of lines
This time we want to take out the lines containing the errors. In the example these are lines 2 to 4. Specify this
range to address, together with the d command:
sandy ~> sed '2,4d' example
This is the first line of an example text.
This is a line not containing any errors.
This is the last line.
sandy ~>
To print the file starting from a certain line until the end of the file, use a command similar to this:
sandy ~> sed '3,$d' example
This is the first line of an example text.
It is a text with erors.
sandy ~>
This only prints the first two lines of the example file.
The following command prints the first line containing the pattern "a text", up to and including the next line
containing the pattern "a line":
Chapter 5. The GNU sed stream editor 64