Live capture a Chrome or Firefox pcap/ng download as it is downloading

dl_livecap.sh

#!/usr/bin/env bash
# This script will detect if there are any new partial download files
# And launch wire/tshark to read them as a live capture.

DL_DIR="$HOME/Downloads"
SHARK_CMD="wireshark -k -i -"
# SHARK_CMD="tshark -r -"
function DL_PARTIALS {
    # Partial names: Chrome=$file.crdownload, Firefox=$file.part, Safari=$file.download, Edge=$file.RaNd0mStr.partial
    find "$DL_DIR" -maxdepth 1 | perl -ne 'print /(.*pcapng\.(part|crdownload|download|[a-zA-Z0-9]+\.partial))/'
}

while true; do
    file="$(DL_PARTIALS)"
    while [ "$file" = "" ]; do sleep 1; file="$(DL_PARTIALS)"; done
    # Don't reopen wireshark if the user closed it for this file
    if [ "$prev_file_id" != "$(stat -c %i $file)" ]; then
        echo "Found download partial \`$file\`"
        tail -f -n +1 $file | $SHARK_CMD 
    else
        sleep 1
    fi  
    prev_file_id="$(stat -c %i $file)"
done