Alternating output in bash for loop from two grep - bash

Question

I'm trying to search through files and extract two pieces of relevant information every time they appear in the file. The code I currently have:
#!/bin/bash
echo "Utilized reads from ustacks output" > reads.txt
str1="utilized reads:"
str2="Parsing"
for file in /home/desaixmg/novogene/stacks/sample01/conda_ustacks.o*; do
reads=$(grep $str1 $file | cut -d ':' -f 3
samples=$(grep $str2 $file | cut -d '/' -f 8
echo $samples $reads >> reads.txt
done
It is doing each line for the file (the files have varying numbers of instances of these phrases) and gives me the output per row for each file:
PopA_15.fq 1081264
PopA_16.fq PopA_17.fq 1008416 554791
PopA_18.fq PopA_20.fq PopA_21.fq 604610 531227 595129
...
I want it to match each instance (i.e. 1st instance of both greps next two each other):
PopA_15.fq 1081264
PopA_16.fq 1008416
PopA_17.fq 554791
PopA_18.fq 604610
PopA_20.fq 531227
PopA_21.fq 595129
...
How do I do this? Thank you

Answer 1

Considering that your Input_file is same as sample shown and number of columns are even on each line with 1 PopA value and other will be with digit values. Following awk may help you in same.
awk '{for(i=1;i<=(NF/2);i++){print $i,$((NF/2)+i)}}' Input_file
Output will be as follows.
PopA_15.fq 1081264
PopA_16.fq 1008416
PopA_17.fq 554791
PopA_18.fq 604610
PopA_20.fq 531227
PopA_21.fq 595129
In case you want to pass output of a command to awk command then you could do like your command | awk command... no need to add Input_file to above awk command.

Answer 2

This is what ended up working for me...any tips for more efficient code are definitely welcome
#!/bin/bash
echo "Utilized reads from ustacks output" > reads.txt
str1="utilized reads:"
str2="Parsing"
for file in /home/desaixmg/novogene/stacks/sample01/conda_ustacks.o*; do
reads=$(grep $str1 $file | cut -d ':' -f 3)
samples=$(grep $str2 $file | cut -d '/' -f 8)
paste <(echo "$samples" | column -t) <(echo "$reads" | column -t) >> reads.txt
done
This provides the desired output described above.