I want to extract the Nth line after a matching pattern using grep
, awk
or sed
.
For example I have this piece of text:
To extract the Nth line after a matching pattern
you want:
awk 'c&&!--c;/pattern/{c=N}' file
e.g.
awk 'c&&!--c;/Revision:/{c=5}' file
would print the 5th line after the text "Revision:"/.
FYI the following idioms describe how to select a range of records given a specific pattern to match:
a) Print all records from some pattern:
awk '/pattern/{f=1}f' file
b) Print all records after some pattern:
awk 'f;/pattern/{f=1}' file
c) Print the Nth record after some pattern:
awk 'c&&!--c;/pattern/{c=N}' file
d) Print every record except the Nth record after some pattern:
awk 'c&&!--c{next}/pattern/{c=N}1' file
e) Print the N records after some pattern:
awk 'c&&c--;/pattern/{c=N}' file
f) Print every record except the N records after some pattern:
awk 'c&&c--{next}/pattern/{c=N}1' file
g) Print the N records from some pattern:
awk '/pattern/{c=N}c&&c--' file
I changed the variable name from "f" for "found" to "c" for "count" where appropriate as that's more expressive of what the variable actually IS.