Extract all ocurrences between delimiters being that they can appear more than one per line-CodePudding

I have a document file.yaml that have something like placeholders to replace:

class: ##TOPIC##-area
  name: myClass
type: Class
secretKey: private-##SECRET_KEY##

so far I've used grep to get the values of placeholders

grep -P '(?<=##).*(?=##)' file.yaml

then, I had those values:

TOPIC
SECRET_KEY

now, we have to introduce new properties that can have more than one placeholder per line

class: ##TOPIC##-area
  name: myClass
type: Class
secretKey: private-##SECRET_KEY##-encoded-##SUFFIX_CODE##

hence, grep no longer worked because the output became:

TOPIC
SECRET_KEY##-encoded-##SUFFIX_CODE

but, I want to have

TOPIC
SECRET_KEY
SUFFIX_CODE

I accept all kinds of suggestions and ideas to solve that. thanks

CodePudding user response：

When you want to use grep, try something like

grep -Eo "##[^#]*##" file.yaml | tr -d '#'

With awk you can have a multi-character separator, that looks easier:

awk -F'##' '{for (i=2; i<=NF;i =2) {print $i}}' file.yaml

CodePudding user response：

Use a negative lookahead to exclude substrings that contain ## in them from the match.

(?<=##)((?!##).)*(?=##)

DEMO

Note that this will also return -encoded- since it's also between a pair of ##. Normally you won't get overlapping matches, but lookarounds aren't considered part of the match, so they don't count as overlapping.