zsh script to pull a date string from a parent directory and write it into an image file's EXIF metadata

add_date.sh

#!/bin/zsh

# Script to add back in missing EXIF creation data metadata using
# exiftool, based on parent folder (which contains date information)
# Naupaka Zimmerman
# naupaka at gmail.com
# September 14, 2015
# Code is licensed CC-0

# Set file incrementer
FILENUM=1

# Save original argument delimiter variable to value
SAVEIFS=$IFS

# Change argument delimiter to end-of-line (no spaces)
IFS=$(echo -en "\n\b")

# Loop through all files in hard-coded image directory of choice
# extract the YYYY-MM-DD date string from the parent folder
# parse it to remove other stuff and newlines and save to a variable
# If image file has 'research' keyword tag and doesn't have a creation
# date set yet, then set it based on the parsed string

for file in $(ls -d1 /Users/naupaka/Pictures/2006/2006-07-30/*)
do
    echo "$FILENUM processing $file"
    DATEMOD=$(echo "$file" | grep -o '\/\d\d\d\d-\d\d-\d\d\/' | sed s@\/@@g | sed s/\-/\:/g | sed s/\n//g)
    DATETIMEMOD=$(echo -n "$DATEMOD 12:00:00")
    exiftool -datetimeoriginal=$DATETIMEMOD -if '$keywords =~ /research/' -if 'not $datetimeoriginal' "$file"
    FILENUM=$((FILENUM+1))
done

# Set the argument delimiter back to what it was when we started
IFS=$SAVEIFS

# to remove all original unmodified files (exiftool makes copies before modifying)
# rm -rv ~/Pictures/**/*original