Copy range of lines to another file based on regex match

Ruby
1

Hi,

I am writing a script to search for a particular string in a file and
then copy all lines starting from matching-line to another file.
Following should make it clear again:

  • search for first occurrence of a particular string in a file
  • find it’s line number
  • copy certain text in all lines or entire line, starting from above
    line number to EOF to another file

I can find the matching line’s number as:

File.foreach(afile) do |line|
if line =~ /(\S+:)(\S+:)(\S+:)8055:(\S+:)(\S+)/
puts “Found match at #{$.}”
lnumber = $.
end
end

But I am not sure how to copy range of line numbers to another file. I
thought about using another File open again and then use range operators
($. == lnumber) as mentioned here,
Pattern Matching , but
wondering if there is any other better way that I might be missing here.
Any suggestions?

thanks,
neuby.r

2

On Wed, Jul 20, 2011 at 7:18 AM, Neubyr N. [email protected] wrote:

I can find the matching line’s number as:
thought about using another File open again and then use range operators
($. == lnumber) as mentioned here,
Pattern Matching , but
wondering if there is any other better way that I might be missing here.
Any suggestions?

Forget about line numbers, you are already iterating over the lines,
just iterate first until that line, then read the rest of the file and
write it out:

File.open(file) do |f|
File.open(output, “w”) do |out|
line = f.gets until line =~ your_regex
out.puts line
out.write f.read
end

Jesus.

3

Neubyr N. wrote in post #1011813:

I am writing a script to search for a particular string in a file and
then copy all lines starting from matching-line to another file.
Following should make it clear again:

  • search for first occurrence of a particular string in a file
  • find it’s line number
  • copy certain text in all lines or entire line, starting from above
    line number to EOF to another file

$ sed -n -e ‘/rx/,$ {s/foo/bar/g; p}’ a_file

:slight_smile:

Kind regards

robert