awk or sed for finding closest pattern to a line number

alirezan · #1 (**permalink**) 10-10-2008

hi guys,

I want to do pattern matching with awk or sed but I don't know how. here's what I want:

I have a line number for a pattern that I have already found using grep, and I know a pattern like "---" that happens a few lines above that certain line number. I want to print out the chunk between "---" and that line number. But here's the catch. the pattern "---" can be between 1 and 20 lines above that line number and I don't know how many lines above ... Also, another catch is that, "---" can happen multiple times in the file but I want the "CLOSEST" to the line number. Here's an example:

Here's the file:

Quote:

---
aaa
bbb
ccc
ddd

---
aaaa
bbbb
cccc
dddd
eeee
ffff
gggg
hhhh

---
jjj
dsf
qqq
www
eee

I found the pattern say qqq to be on line 20. I want to find the first --- before pattern qqq (line 20) and I want to print the entire chunk from --- till the qqq pattern printed out.

Can someone help me out here please?
Thanks

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