Parse multiple sections of data into separate files

You should gain a lot by passing the log file just once through awk. This means combining all the regexps into one. If you don't want to do this in your scope.txt file, then do it before calling awk. For example,

sed <scope.txt 's|^/\^|(|; s|\$/$|)|; $!s/$/|/' | tr -d '\n' >pattern

zcat $file | bro-cut -d |
awk '
BEGIN{ getline pat <"pattern"; pat = "^(" pat ")$" }
$3 ~ pat || $5 ~ pat
'  >~/$file

The sed replaces the /^ and $ surrounding each regexp line with a enclosing () pair, adds an | at the end of the line, and puts the result all on one line into file pattern. This file is therefore all the patterns or-ed together. The missing ^(...)$ is added in the awk script BEGIN statement, which reads the pattern file into variable pat.

The above replaces your inner for loop, and the sort|uniq.

Take a look at ENDFILE blocks (GNU awk specific). You could run something along the lines of

awk     'BEGINFILE { a = ""}
         /prop1/   { a=$NF $2 $1}    ## Change this if necessary
         ENDFILE   { if (a != "") print FILENAME, a}' ./node*.log