Search text for multiple lines matching string 1 which are not separated by string 2 - regex

Question

I've got a file looking like this:
abc|100|test|line|with|multiple|information|||in|different||fields
abc|100|another|test|line|with|multiple|information|in||different|fields|
abc|110|different|looking|line|with|some|supplementary|information
abc|100|test|line|with|multiple|information|||in|different||fields
abc|110|different|looking|line|with|some|other|supplementary|information
abc|110|different|looking|line|with|additional||information
abc|100|another|test|line|with|multiple|information|in||different|fields|
abc|110|different|looking|line|with|supplementary|information
I'm looking for a regexp to use with sed / awk / (e)grep (it actually doesn't matter to me which of these as all would be fine) to find the following in the above mentioned text:
abc|100|test|line|with|multiple|information|||in|different||fields
abc|110|different|looking|line|with|some|other|supplementary|information
abc|110|different|looking|line|with|additional||information
I want to get back a |100| line if it is followed by at least two |110| lines before another |100| line appears. The result should contain the initial |100| line together with all |110| lines that follow but not the following |100| line.
sed -ne '/|100|/,/|110|/p'
provides me a list of all |100| lines which are followed by at least one |110| line. But it doesn't check, if the |110| line has been repeated more than once. I get back results I don't look for.
sed -ne '/|100|/,/|100|/p'
returns a list of all |100| lines and the content between the next |100| line including the next |100| line.
Trying to find lines between search patterns always was a nightmare to me. I spent hours of try and error on similar problems which finally worked. But I never really understood why. I hope, s.o. might be so kind to save me of the headache this time and maybe explain how the pattern does the work. I'm quite sure, I'll face this kind of problem again and then I finally could help myself.
Thank you for any help on this one!
Regards
Manuel

Answer 1

I'd do this in awk.
awk -F'|' '$2==100&&c>2{print b} $2==100{c=1;b=$0;next} $2==110&&c{c++;b=b RS $0;next} {c=0}' file
Broken out for easier reading:
awk -F'|' '
# If we're starting a new section and conditions have been met, print buffer
$2==100 && c>2 {print b}
# Start a section with a new count and a new buffer...
$2==100 {c=1;b=$0;next}
# Add to buffer
$2==110 && c {c++;b=b RS $0}
# Finally, zero everything if we encounter lines that don't fit the pattern
{c=0;b=""}
' file
Rather than using a regex, this steps through the file using the field delimiters you've specified. Upon seeing the "start" condition, it begins keeping a buffer. As subsequent lines match your "continue" condition, the buffer grows. Once we see the start of a new section, we print the buffer if the the counter is big enough.
Works for me on your sample data.

Answer 2

Here's a GNU awk specific answer: use |100| as the record separator, |110| as the field separator, and look for records with at least 3 fields.
gawk '
BEGIN {
# a newline, the first pipe-delimited column, then the "100" value
RS="(\n[^|]+[|]100[|])"
FS="[|]110[|]"
}
NF >= 3 {print RT $0} # RT is the actual text matching the RS pattern
' file

Answer 3

In AWK, the field separator is set to a pipe character and the second field is compared to 100 and 110 per line. $0 represents a line from the input file.
BEGIN { FS = "|" }
{
if($2 == 100) {
one_hundred = 1;
one_hundred_one = 0;
var0 = $0
}
if($2 == 110) {
one_hundred_one += 1;
if(one_hundred_one == 1 && one_hundred = 1) var1 = $0;
if(one_hundred_one == 2 && one_hundred = 1) var2 = $0;
}
if(one_hundred == 1 && one_hundred_one == 2) {
print var0
print var1
print var2
}
}
awk -f foo.awk input.txt
abc|100|test|line|with|multiple|information|||in|different||fields
abc|110|different|looking|line|with|some|other|supplementary|information
abc|110|different|looking|line|with|additional||information