Searching through .txt files in different folders for a specific string - bash

Question

New to bash scripting here.
I have a folder (/month) which contains more folders (/month/jan, /month/feb, /month/mar etc.) and within these folders there are .txt files (Sales11.txt, Sales17.txt etc.). These text files contain a staff ID number and their sales results as a percentage
e.g Sales11.txt contents are
20456 78
20512 46
20498 67
20645 88
I am looking to search through these .txt files for a Staff ID number and when this exists to make a text file in the staff members folder /staff/20512 (which already exist) by the name Jan.txt or whichever month it has occurred in. The contents of the Jan.txt file will be the name of the sales file and the percent. There could be more than one sales event in each month.
Example output file would be to /staff/20512 the file named Jan.txt which would contain
Sales11 46
Sales17 98
I think I need to include a if loop and use an array to search through the different folders and within this use the grep function to search for the staff id.
I’m not 100% on what order these should be included and how to make use of multiple different arrays in a single script, if that is even possible. My first attempt is below.
while read STAFFID ; do
ARRSTAFF=($STAFFID)
ARRMON=($MONTHS)
ARRSALE=($SALES)
if [ grep -r “/month/${ARRMON}/${ARRSALE}.txt” -e “${ARRSTAFF}” ]; then
echo “${ARRSALE[0]} ${ARRSALE[1]}” >> Staff/${ARRSTAFF[0]}/${ARRMON}.txt
fi
done < contents/Staff.txt

Answer 1

Since there are no staff IDs in the data that fail to appear Staff.txt, the latter provides no additional information. It can be ignored. Every line in every daily report file will correspond to one line in one of the generated per-staff files. It is simpler, then, to read each daily file just once, and to handle all its contents in that run.
Furthermore, it's unclear whether there is any particular advantage to building up arrays in memory. Doing so makes the script more complicated, and that's a lose unless you gain something substantial in return.
Here's one way you could approach the problem:
# keep one level of backups of existing target files
for file in /staff/*.txt; do
mv "${file}" "${file}.bak"
done
# Process the data files once each
for file in /month/*/*.txt; do
# extract relevant filename parts
month=$(basename $(dirname "${file}"))
filebase=$(basename "${file%.txt}")
# read and report out all the lines of the file
while read staffid value; do
echo "$filebase" "$value" >> "/staff/${staffid}/${month}.txt"
done < "$file"
done
That assumes primarily that the daily report files are formatted as you describe, with no extra fields and no whitespace within the fields. It does not rely on Staff.txt at all.