How can I match an exact pattern with sed -n

Question

I have a file test.txt

---
kind: ClusterRole
metadata:
kind: ClusterRoleBinding
metadata:
subjects:
roleRef:
  kind: ClusterRole
  name: bla

And need this output with sed (just the line that matches the exact pattern)

kind: ClusterRole
metadata:

sed -n '/kind: ClusterRole/,/metadata/p' test.txt

kind: ClusterRole
metadata:
kind: ClusterRoleBinding
metadata:
  kind: ClusterRole
  name: bla

is showing ClusterRole, ClusterRoleBinding and additional indented ClusterRole

sed -n '/kind: ClusterRole\b/,/metadata/p' test.txt
sed -n '/\<kind: ClusterRole\>/,/metadata/p' test.txt

Both of the above output to nothing what am I doing wrong? just so it's clear and I'm not getting any grep -B 2 suggestions ;-) this is an example file, the original file is a lot bigger and has hundreds of ClusterRoles so I need to figure out how to match the exact pattern.

Thank you!

lema

It's not very clear why you would want to do this (you don't need sed to produce the output as described). However: `sed -n '/^kind: ClusterRole$/,${1,/^metadata:$/p}' file.txt` — jhnc, Feb 15 '20 at 02:33
or `sed -n '/^kind: ClusterRole$/,${p;/^metadata:$/q}' file.txt` to not waste time reading the rest of the file — jhnc, Feb 15 '20 at 02:42

Nitish · Answer 1 · 2020-02-15T12:47:14.517

0

If you just need to search the exact multiple lines, then you can achieve it using pcregrep

pcregrep -M 'kind: ClusterRole(\n)metadata:' test.txt

where -M, --multiline allow patterns to match more than one line.

More details can be found in this SO post.

Edit:

You can also use grep

grep -Pazo 'kind: ClusterRole\nmetadata:' test.txt

Reference: this SO post

edited Feb 15 '20 at 12:47

answered Feb 15 '20 at 12:25

Nitish

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score 0 · Accepted Answer · answered Feb 15 '20 at 23:22

0

You should include start-of-line (^) and end-of-line ($) in your pattern.

answered Feb 15 '20 at 23:22

Walter A

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score 0 · Answer 3 · answered Feb 16 '20 at 12:27

This might work for you (GNU sed):

sed -n 'N;/^kind: ClusterRole\nmetadata:$/p;D' file

Append the next line and print the lines if it matches. Delete the first line and repeat.

If you only want the first match, use:

sed -n 'N;/^kind: ClusterRole\nmetadata:$/{p;q};D' file

How can I match an exact pattern with sed -n

3 Answers3