Question

I am trying to parse some nginx logs by date. I have written an awk oneliner to find all matching logs for a day, like:

awk '/05\/May\/2012/ { print $0;}' /var/log/nginx/access.log  

What I want to do is to loop over some days and months using bash. Here is what I have got

#!/bin/bash

for h in 2012
do
    for i in Apr May
    do
        for j in 01 02 03 04 05
        do
            echo "/${j}\/${i}\/${h}/"
            search_string="'/${j}\/${i}\/${h}/ { print \$0;}'"
            echo $search_string;
            awk $search_string /var/log/nginx/access.log  
            echo "${h} ${i} ${j} done" 
        done
    done
done

However, this fails on awk line with:

 awk: 1: unexpected character '''

It seems like I need to escape some variables, but I haven’t found a solution so far.

Answer 1

Single quotes are not needed.
Double quotes are needed.

search_string="/${j}\/${i}\/${h}/ { print \$0;}"
awk "$search_string" /var/log/nginx/access.log