Bash: Working with CSV file to build a loop and save the result - bash

Question

Using Bash, I'm wanting to get a list of email addresses from a CSV file to do a recursive grep search on it for a bunch of directories looking for a match in specific metadata XML files, and then also tallying up how many results I find for each address throughout the directory tree (i.e. updating the tally field in the same CSV file).
accounts.csv looks something like this:
updated to more accurately reflect real-world data
email,date,bar,URL,"something else",tally
address#somewhere.com,21/04/2015,1.2.3.4,https://blah.com/,"blah blah",5
something#that.com,17/06/2015,5.6.7.8,https://blah.com/,"lah yah",0
another#here.com,7/08/2017,9.10.11.12,https://blah.com/,"wah wah",1
For example, if we put address#somewhere.com in $email from the list, run
grep -rl "${email}" --include=\*_meta.xml --only-matching | wc -l
on it and then add that result to the tally column.
At the moment I can get the first column of that CSV file (minus the heading/first line) using
awk -F"," '{print $1}' accounts.csv | tail -n +2
but I'm lost how to do the looping and also the writing of the result back to the CSV file...
So for instance, with another#here.com if we run
grep -rl "${email}" --include=\*_meta.xml --only-matching | wc -l
and the result is say 17, how can I update that line to become:
another#here.com,7/08/2017,9.10.11.12,https://blah.com/,"wah wah",17
Is this possible with maybe awk or sed?
This is where I'm up to:
#!/bin/bash
# make temporary list of email addresses
awk -F"," '{print $1}' accounts.csv | tail -n +2 > emails.tmp
# loop over each
while read email; do
# count how many uploads for current email address
grep -rl "${email}" --include=\*_meta.xml --only-matching | wc -l
done < emails.tmp
XML Metadata looks something like this:
<?xml version="1.0" encoding="UTF-8"?>
<metadata>
<identifier>SomeTitleNameGoesHere</identifier>
<mediatype>audio</mediatype>
<collection>opensource_movies</collection>
<description>example <br /></description>
<subject>testing</subject>
<title>Some Title Name Goes Here</title>
<uploader>another#here.com</uploader>
<addeddate>2017-05-28 06:20:54</addeddate>
<publicdate>2017-05-28 06:21:15</publicdate>
<curation>[curator]email#address.com[/curator][date]20170528062151[/date][comment]checked for malware[/comment]</curation>
</metadata>

Answer 1

how to do the looping and also the writing of the result back to the CSV file
awk does the looping automatically. You can change any field by assigning to it. So to change a tally field (the 6th in each line) you would do $6 = ....
awk is a great tool for many scenarios. You probably can safe a lot of time in the future by investing some minutes in a short tutorial now.
The only non-trivial part is getting the output of grep into awk.
The following script increments each tally by the count of *_meta.xml files containing the given email address:
awk -F, -v OFS=, -v q=\' 'NR>1 {
cmd = "grep -rlFw " q $1 q " --include=\\*_meta.xml | wc -l";
cmd | getline c;
close(cmd);
$6 = c
} 1' accounts.csv
For simplicity we assume that filenames are free of linebreaks and email addresses are free of '.
To reduce possible false positives, I also added the -F and -w option to your grep command.
-F searches literal strings; without it, searching for a.b#c would give false positives for things like axb#c and a-b#c.
-w matches only whole words; without it, searching for b#c would give a false positive for ab#c. This isn't 100% safe, as a-b#c would still give a false positive, but without knowing more about the structure of your xml files we cannot fix this.

Answer 2

A pipeline to reduce the number of greps:
grep -rHo --include=\*_meta.xml -f <(awk -F, 'NR > 1 {print $1}' accounts.csv) \
| gawk -F, -v OFS=',' '
NR == FNR {
# store the filenames for each email
if (match($0, /^([^:]+):(.+)/, m)) tally[m[2]][m[1]]
next
}
FNR > 1 {$4 = length(tally[$1])}
1
' - accounts.csv

Answer 3

Here is a solution using single awk command to achieve this. This solution will be highly performant as compared to other solutions because it is scanning each XML file only once for all the email addresses found in first column of the CSV file. Also it is not invoking any external command or spawning a sub0shell anywhere.
This should work in any version of awk.
cat srch.awk
# function to escape regex meta characters
function esc(s, tmp) {
tmp = s
gsub(/[&+.]/, "\\\\&", tmp)
return tmp
}
BEGIN {FS=OFS=","}
# while processing csv file
NR == FNR {
# save escaped email address in array em skipping header row
if (FNR > 1)
em[esc($1)] = 0
# save each row in rec array
rec[++n] = $0
next
}
# this block will execute for eaxh XML file
{
# loop each email and save count of matched email in array em
# PS: gsub return no of substitutionx
for (i in em)
em[i] += gsub(i, "&")
}
END {
# print header row
print rec[1]
# from 2nd row onwards split row into columns using comma
for (i=2; i<=n; ++i) {
split(rec[i], a, FS)
# 6th column is the count of occurrence from array em
print a[1], a[2], a[3], a[4], a[5], em[esc(a[1])]
}
}
Use it as:
awk -f srch.awk accounts.csv $(find . -name '*_meta.xml') > tmp && mv tmp accounts.csv

Answer 4

A script that handles accounts.csv line by line and replaces the data in accounts.new.csv for comparison.
#! /bin/bash
file_old=accounts.csv
file_new=${file_old/csv/new.csv}
delimiter=","
x=1
# Copy file
cp ${file_old} ${file_new}
while read -r line; do
# Skip first line
if [[ $x -gt 1 ]]; then
# Read data into variables
IFS=${delimiter} read -r address foo bar tally somethingelse <<< ${line}
cnt=$(find . -name '*_meta.xml' -exec grep -lo "${address}" {} \; | wc -l)
# Reset tally
tally=$cnt
# Change line number $x in new file
sed "${x}s/.*/${address} ${foo} ${bar} ${tally} ${somethingelse}/; ${x}s/ /${delimiter}/g" \
-i ${file_new}
fi
((x++))
done < ${file_old}
The input and ouput:
# Input
$ find . -name '*_meta.xml' -exec cat {} \; | sort | uniq -c
2 address#somewhere.com
1 something#that.com
$ cat accounts.csv
email,foo,bar,tally,somethingelse
address#somewhere.com,bar1,foo2,-1,blah
something#that.com,bar2,foo3,-1,blah
another#here.com,bar4,foo5,-1,blah
# output
$ ./test.sh
$ cat accounts.new.csv
email,foo,bar,tally,somethingelse
address#somewhere.com,bar1,foo2,2,blah
something#that.com,bar2,foo3,1,blah
another#here.com,bar4,foo5,0,blah