sed match pattern and act on x lines after

Question

I'm trying to find a way to comment out a block (multiple lines) in a configuration file. I'd like to match the first line but also act on each line after that.

sed '/\/Some\/Foo\/Bar\/String/' config.file

The following example "code" is what I'm trying to match and comment out. The block will always end with a } but I also know the number of lines after the pattern match so this one would be pattern line + 6.

foo { '/Some/Foo/Bar/String' :
    key1 => value1,
    key2 => value2,
    key3 => value3,
    key4 => value4,
    key5 => value5,
}

Results after sed command

#foo { '/Some/Foo/Bar/String' :
#    key1 => value1,
#    key2 => value2,
#    key3 => value3,
#    key4 => value4,
#    key5 => value5,
#}

Answer 1

sed allows us to define ranges of lines and then apply substitutions only within those ranges. We can define a range starting with a line containing Some/Foo/Bar/String and ending with a line containing } and then apply a substitute command to comment out those lines:

$ sed '\|/Some/Foo/Bar/String|,/}/ s/^/#/' file
#foo { '/Some/Foo/Bar/String' :
#    key1 => value1,
#    key2 => value2,
#    key3 => value3,
#    key4 => value4,
#    key5 => value5,
#}

Details

• \|/Some/Foo/Bar/String|, /}/

  This defines the range. It could have been written as /\/Some\/Foo\/Bar\/String/, /}/ but, to avoid backslashes, I used | as the delimiter in place of / for the first regex.

• s/^/#/

  This is applied only to lines in the range and it comments them out.