Select the next line after match regex

Question

I'm currently using a scanning software "Drivve Image" to extract certain information from each paper. This software enables certain Regex code to be run if needed. It seems to be run with the UltraEdit Regex Engine.

I get the following scanned result:

 1. 21Sid1
 2. Ordernr
 3. E17222
 4. By
 5. Seller

I need to search the string for the text Ordernr and then pick the following line E17222 which in the end will be said filename of the scanned document. I will never know the exact position of these two values in the string. That is why I need to focus on Ordernr because the text I need will always follow as the next line.

My requirements are such that I need the E17222 to be the only thing in the match result for this to work. I am only allowed to type plain regular expressions.

There is a great thread already: Regex to get the words after matching string

I've tested " \bOrdernr\s+\K\S+ "which works great..

Had it not been that the software don't allow for /K to be used. Are there any other ways of implementing \K?

Continuation

Though If the sample text involves a character behind "Ordernr" the current answer doesn't work to the extent I need. Like this sample:

21Sid1

Ordernr 1

E17222

By

Seller

The current solution picks up "1" and not the "next line" which would be "E17222". in the matched group. Needed to point that out for further involvement on the issue.

Answer 1

Description

ordernr[\r\n]+([^\r\n]+)

This regular expression will do the following:

• find the ordernr substring
• place the line following ordernr capture group 1

Example

Live Demo

https://regex101.com/r/dQ0gR6/1

Sample text

 1. 21Sid1
 2. Ordernr
 3. E17222
 4. By
 5. Seller

Sample Matches

[0][0] = Ordernr
 3. E17222
[0][1] =  3. E17222

Explanation

NODE                     EXPLANATION
----------------------------------------------------------------------
  ordernr                  'ordernr'
----------------------------------------------------------------------
  [\r\n]+                  any character of: '\r' (carriage return),
                           '\n' (newline) (1 or more times (matching
                           the most amount possible))
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    [^\r\n]+                 any character except: '\r' (carriage
                             return), '\n' (newline) (1 or more times
                             (matching the most amount possible))
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------

Alternativly

To just capture the line using a look-around so that ordernr is not included in capture group 0 and to accommodate all the variation of \r and \n

(?<=ordernr\r|ordernr\n|ordernr\r\n)[^\r\n]+

Live Demo

https://regex101.com/r/pA4fD4/2