regexp and sed find block of string in multiline block untill it end with space

Question

I try to capture those blocks of strings and comment on them using regexp and sed. each block separated with space

some text here 
some text here 

AppServer1:
  name: ${AppServer1.name}
  ip: ${AppServer1.ip}
   
some text here 
some text here 

AppServer2:
  name: ${AppServer1.name}
  ip: ${AppServer1.ip}

some text here 
some text here

I try with this regexp:

sed E '/./{H;1h;$!d} ; x ; s/[^\$AppServer1](AppServer1)/#\1/gi'

but the result is :

 #AppServer1:
      name: $#{AppServer1.name}
      ip: $#{AppServer1.ip}

what im missing here to comment the full string to be :

#AppServer1:
#      name: ${AppServer1.name}
#      ip: ${AppServer1.ip}

anubhava · Accepted Answer · 2021-08-10T11:52:34.323

3

Using gnu-sed, you can do this:

sed '/^AppServer1/I{:a; /^[[:blank:]]*$/!{s/.*/#&/; n; ba;} }' file

some text here
some text here

#AppServer1:
#  name: ${AppServer1.name}
#  ip: ${AppServer1.ip}

some text here
some text here

AppServer2:
  name: ${AppServer1.name}
  ip: ${AppServer1.ip}

some text here
some text here

Details:

/^AppServer1/I: Search for AppServer1 case insensitive
{: Block start
- :a: Make label a
- /^[[:blank:]]*$/! If a line is not a blank line
- {s/.*/#&/; n; ba;}: Prepend each line with #, read next line and goto label a
}: Block end

Using awk you can do this:

awk '/^AppServer1/ {b=1} b && !NF {b=0} b {$0 = "#" $0} 1' file

some text here
some text here

#AppServer1:
#  name: ${AppServer1.name}
#  ip: ${AppServer1.ip}

some text here
some text here

AppServer2:
  name: ${AppServer1.name}
  ip: ${AppServer1.ip}

some text here
some text here

edited Aug 10 '21 at 11:52

answered Aug 10 '21 at 11:33

anubhava

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Thanks but its abit problematic to use awk , in my case ... – user63898 Aug 10 '21 at 11:43
I have provided a sed solution as well – anubhava Aug 10 '21 at 11:44
Thank! how do i make the AppServer1 to be not case sensetive in the regexp ? – user63898 Aug 10 '21 at 11:46
also can you please explain what the sed expretion is doing ? – user63898 Aug 10 '21 at 11:48
ok check updated answer for explanation and case ignore match – anubhava Aug 10 '21 at 11:54
can you please check this question https://stackoverflow.com/questions/68740324/sed-regexp-find-block-of-string-in-multiline-block-and-remove-string-untill-it-e – user63898 Aug 11 '21 at 10:33
sure, let me check it now. – anubhava Aug 11 '21 at 13:38
can you please check this question : https://stackoverflow.com/questions/68793203/sed-regexp-add-xml-comment-around-xml-block/68795386#68795386 – user63898 Aug 16 '21 at 04:38

Ionuț G. Stan · Answer 2 · 2021-08-10T13:03:42.887

A simpler sed solution might be this, if you're ok with having the final empty line commented too:

sed '/^AppServer1:/,/^[[:space:]]*$/s/^/# /' lines.txt

some text here
some text here

# AppServer1:
#   name: ${AppServer1.name}
#   ip: ${AppServer1.ip}
# 
some text here
some text here

AppServer2:
  name: ${AppServer1.name}
  ip: ${AppServer1.ip}

some text here
some text here

It uses a sed range pattern, denoted by a comma (,). The start of the range is /^AppServer1:/, i.e., any line that starts (^) with AppServer1:. The end of the range is an empty line or one that contains only whitespace characters: /^[[:space:]]*$/, where ^: start of line; [[:space:]]*: zero or more (*) whitespace characters ([[:space:]]); $: end of line.

Next comes the [s]ubstitution command — s/^/# / — which substitutes the start of the line ^ with the sequence # on all lines within the matched range (inclusive end).

If you want a case-insensitive match, you need GNU sed. In that case you can add the I flag to the start-of-range pattern. This flag is not available on macOS sed, though.

score 0 · Answer 3 · answered Aug 10 '21 at 17:55

Assuming the lines in your input that look empty truly are empty, you can do this using any awk in any shell on every Unix box:

$ awk -v RS= -v ORS='\n\n' '/^AppServer1:/{gsub(/^|\n/,"&#")} 1' file
some text here
some text here

#AppServer1:
#  name: ${AppServer1.name}
#  ip: ${AppServer1.ip}

some text here
some text here

AppServer2:
  name: ${AppServer1.name}
  ip: ${AppServer1.ip}

some text here
some text here

regexp and sed find block of string in multiline block untill it end with space

3 Answers3