Shell Programming and Scripting

This is regarding using awk tool to find lines matching between 2 patterns.

Code:

cat file | awk '/pat1/,/pat2/'

But it's not working as expected in the following case.

[1]

If pat1 also comes after pat2 then it's matching whole file after pat1.

e.g.

Code:

# > cat -n file
     1  First line
     2  contains pat1
     3  intermediate lines
     4  pat2
     5  some line
     6  again here pat1
     7  end of file

# > cat file | awk '/pat1/,/pat2/'
contains pat1
intermediate lines
pat2
again here pat1
end of file

Here I want only lines between first pat1 and first pat2 and want to ignore all other lines.
How to do that? Can we use sed so that this problem does not arise?

One solution that came in my mind is that change only the first pat1 by say PAT1 and then use awk '/PAT1/,/pat2/', but I am sure there are better solutions.

Something like this?

Code:

awk '/pat1/{p=1}/pat2/{print;exit}p' file

Code:

gawk -vRS="pat2" '{gsub(/.*pat1/,"");print;exit}' file

Code:

gawk '/pat1/,/pat2/ {if($0~/pat2/){print;exit}else{print}}' file

Have you tried your command?