awk to pick out more than one line

Applications UNIX Desktop Questions & Answers
1

This really is a dummy question but I'm stuck and out of time... I have a large file and out of it I only want to pick out lines starting with either "Pressure" or "N". I still need these lines to be in their original order.

example of text

Pressure 3 
N 2
N 3
bla bla
bla bla
Pressure 4
bla bla
N 5

I would like

Pressure 3
N 2
N3 
Pressure 4
N 5

I can use awk (see below) but can only get the coding correct to pick out one line at a time.

awk '/Pressure/, /[Pa]/' all > check.txt
awk '/  N  /' all  > check.txt

I need awk to scan a line at a time so that the Pressure lines and N lines are still printed in the correct order.

Any help appreciated,

Jenny

2 
sed -n '/^Pressure/p;/^N/p' file
3 
awk '/^Pressure/ || /^N/' infile

You don't even need awk, grep would do it too:

grep -E "^Pressure|^N" infile
4

Fantastic -thanks!