simply pass a variable into a regex OR string search in awk - regex

Question

This is driving me nuts. Here's what I want to do, and I've made it simple as possible:
This is written into an awk script:
#!/bin/bash/awk
# pass /^CHEM/, /^BIO/, /^ENG/ into someVariable and search file.txt
/someVariable/ {print NR, $0}
OR I would be fine with (but like less)
#!/bin/bash/awk
# pass "CHEM", "BIO", "ENG" into someVariable and search file.txt
$1=="someVariable" {print NR, $0}
I find all kinds of stuff on BASH/SHELL variables being passed but I don't want to learn BASH programming to simply pass a value to a variable.
Bonus: I actually have to search 125 values in each document, with 40 documents needing to be evaluated. It can't hurt to ask a bit more, but how would I take a separate file of these 125 values, pass them individually to someVariable?
I have all sorts of ways to do this in BASH but I don't understand them and there has got to be a way to simply cycle through a set of search terms dynamically in awk (perhaps by an array since I do not believe a list exists yet)
Thank you as I am tired of beating my head into a wall.

Answer 1

I actually have to search 125 values in each document, with 40 documents needing to be evaluated.
Let's put the strings that we want to search for in file1:
$ cat file1
apple
banana
pear
Let's call the file that we want to search file2:
$ cat file2
ear of corn
apple blossom
peas in a pod
banana republic
pear tree
To search file2 for any of the words in file1, use:
$ awk 'FNR==NR{a[$1]=1;next;} ($1 in a){print FNR,$0;}' file1 file2
2 apple blossom
4 banana republic
5 pear tree
How it works
FNR==NR{a[$1]=1;next;}
This stores every word that we are looking for as a key in array a.
In more detail, NR is the number of lines that awk has read so far and FNR is the number of lines that awk has read so far from the current file. Thus, if FNR==NR, we are still reading the first named file: file1. For every line in file1, we set a[$1] to 1.
next tells awk to skip the rest of the commands and start over with the next line.
($1 in a){print FNR,$0;}
If we get to this command, we are on file2.
If the first field is a key in array a, then we print the line number and the line.

Answer 2

"...For example I wanted the text between two regexp from file2. Let's say /apple/, /pear/. How would I substitute and extract the text between those two regexp?..."
while read b e; do awk "/^$b$/,/^$e$/" <(seq 1 100); done << !
> 1 5
> 2 8
> 90 95
> !
1
2
3
4
5
2
3
4
5
6
7
8
90
91
92
93
94
95
Here between the two exclamation points is the input for ranges and as the data file I used 1..100. Notice the double quotes instead of single quotes in the awk script.
If you have entered start end values in the file ranges, and your data in file data
while read b e; do awk "/^$b$/,/^$e$/" data; done < ranges
If you want to print the various ranges to different files, you can do something like this
while read b e; do awk "/^$b$/,/^$e$/ {print > $b$e}" data; done < ranges

Answer 3

A slight variation that you may or may not like... I sometimes use the BEGIN section to read the contents of a file into an array...
BEGIN {
count = 1
while ("cat file1" | getline)
{
a[count] = $3
count++
}
}
The rest continues in much the same way. Anyway, maybe that works for you as well.