Parsing Apache logs with bash

One for GNU awk, that outputs in the order the data was fed in (ie. chronological data such as log records should be output in that order):

$ gawk '                     # using GNU awk
BEGIN {
    a[""][""]                # initialize a 2D array
}
{
    split($4,t,/[/:]/)       # split datetime 
    my=t[2] OFS t[3]         # my=month year
    if(!(my in mye)) {       # if current my unseen
        mye[my]=++myi        # update month year exists array with new index
        mya[myi]=my          # chronology is made
    }
    a[mye[my]][$1]++         # update record to a hash
}
END {                        # in the end
    # PROCINFO["sorted_in"]="@val_num_desc"  # this may work for ordering visits
    for(i=1;i<=myi;i++) {    # in fed order 
        print mya[i]         # print month year
        for(j in a[i])       # then related ips in no particular order
            print j,a[i][j]  # output ip and count
    }
}' file

Output:

Dec 2019
1.1.1.1 2
2.2.2.2 1
Jan 2020
2.2.2.2 1
3.3.3.3 1
Feb 2020
1.1.1.1 1
4.4.4.4 3

Though your sample expected output doesn't look to match your shown sample, based on your shown sample output and description, could you please try following. Also since this is a log file I will go with field separators method of awk since logs will be of fixed pattern.

awk -F':| |-|/+|]' '
{
  ind[$7 OFS $8 OFS $1]++
  value[$7 OFS $8 OFS $1]=$1
}
END{
  for(i in value){
    split(i,arr," ")
    print arr[1],arr[2] ORS value[i],ind[i]
  }
}' Input_file

Explanation: Adding detailed explanation for above.

awk -F':| |-|/+|]' '                             ##Starting awk program from here and setting field separators as : space - / ] here.
{
  ind[$7 OFS $8 OFS $1]++                        ##Creating ind array whose index is 7th 8th and 1st field and keep increasing value with 1 here.
  value[$7 OFS $8 OFS $1]=$1                     ##Creating value with index of 7th, 8th and 1st field and its value is 1st field.
}
END{                                             ##Starting END block of this program from here.
  for(i in value){                               ##Traversing through value elements here.
    split(i,arr," ")                             ##Splitting i into array arr with delimiter as space here.
    print arr[1],arr[2] ORS value[i],ind[i]      ##Printing 1st and 2nd element of arr with ORS(new line) and array value and ind value here.
  }
}' Input_file                                    ##Mentioning Input_file name here.

try this..

shell:

#!/usr/bin/env bash
LOG_FILE=$1

#regex to find mmm/yyyy
dateUniq=`grep -oP '(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\/\d{4}' $LOG_FILE | sort | uniq`


for i in $dateUniq
do  
    #output mmm yyyy
    echo $i | sed 's/\// /g'
    
    #regex to find ip
    ipUniq=`grep $i $LOG_FILE | grep -oP '(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)'  | sort | uniq`
    
    for x in $ipUniq
    do  
        count=`grep $i $LOG_FILE |grep -c $x`
        #output count ip
        echo $count $x
    done
    echo
done

output:

Dec 2019
2 1.1.1.1
1 2.2.2.2

Feb 2020
1 1.1.1.1
3 4.4.4.4

Jan 2020
1 2.2.2.2
1 3.3.3.3

for a quick summarize access log. just run below commands.

cat /var/log/apache2/access.log|awk '{print $1}'|sort -nr |uniq -c |sort -nr |head -n 25