Print line after multiline match with sed - regex

Question

I am trying to create a script to pull out an account code from a file. The file itself is long and contains a lot of other data, but I have included below an excerpt of the part I am looking at (there is other contents before and after this excerpt)
The section of the file I am interested in sometimes look like this
Account Customer Order No. Whse Payment Terms Stock No. Original Invoice No.
VIN No.
AAAAAA01 9999 1000 30 days
and sometimes it looks like this
Account Customer Order No. Whse Payment Terms Stock No. Original Invoice No.
AAAAAA01 9999 1000 30 days
(one field cut off the end, where that field had been wrapping down onto it's own line)
I know I can use | tr -s ' ' | cut -d ' ' -F 1 to pull the code once I have the line it is on, but that is not a set line number (the content before this section is dynamic).
I am starting by trying to handled the case with the extra field, I figure it will be easy enough to make that an optional match with ?
The number of spaces used to separate the fields can change as this is essentially OCRed.
A few of my attempts so far - (assume the file is coming in from STDIN)
| sed -n '/\s*Account\s\+Customer Order No\.\s\+Whse\s\+Payment Terms\s\+Stock No\.\s\+Original Invoice No\.\s\+VIN No\.\s*/{n;p;}'
| sed -n '/\s*Account\s\+Customer Order No\.\s\+Whse\s\+Payment Terms\s\+Stock No\.\s\+Original Invoice No\.\s*\n\s*VIN No\.\s*/{n;p;}'
| sed -n '/\s*Account\s\+Customer Order No\.\s\+Whse\s\+Payment Terms\s\+Stock No\.\s\+Original Invoice No\.\s*\r\s*VIN No\.\s*/{n;p;}'
| sed -n '/\s*Account\s\+Customer Order No\.\s\+Whse\s\+Payment Terms\s\+Stock No\.\s\+Original Invoice No\.\s*\r\n\s*VIN No\.\s*/{n;p;}'
These all failed to match whatsoever
| sed -n '/\s*Account\s\+Customer Order No\.\s\+Whse\s\+Payment Terms\s\+Stock No\.\s\+Original Invoice No\.\s*/,/\s\*VIN No\.\s*/{n;p;}'
This at least matched something, but frustratingly printed the VIN No. line, followed by every second line after it. It also seems like it would be more difficult to mark as an optional part of the expression.
So, given an input of the full file (including either of the above excerpts), I am looking for an output of either
AAAAAA01 9999 1000 30 days
(which I can then trim to the required data) or AAAAAA01 if there is an easier way of getting straight to that.

Answer 1

This might work for you (GNU sed):
sed -n '/Account/{n;/VIN No\./n;p}' file
Use sed with the -n switch, this makes sed act like grep i.e. only print lines explicitly using the commands P or (this case) p.
/Account/ match a line with the pattern Account
For the above match only:
n normally this would print the current line and then read the next line into the pattern space, but as the -n is in action no printing takes place. So now the pattern space contains the next line.
/VIN No\./n If the current line contains Vin No effectively empty the pattern space and read in the next line.
p print whatever is currently in the pattern space.
So this a condition within a condition. When we encounter Action print either the following line or the line following that.

Answer 2

awk '/^\s*Account\s\+Customer Order No\.\s\+Whse\s\+Payment Terms\s\+Stock No\.\s\+Original Invoice No\.$/ {
getline;
if (/^\s*VIN No\.$/) getline;
print;
exit;
}'

Answer 3

Going strictly off your input, in both cases the desired field is on the last line. So to print the first field of the last line,
awk 'END {print $1}'
Result
AAAAAA01