SSC comment thread analyzer

#!/bin/bash
# Use SSC post/OT URLs as parameters
# Prints number of comments
# Prints number of comments, number of top-level comments,
# average length of thread under a top-level comment, longest thread

for i in "$@"; do
    filename=$(sed 's+https\?://slatestarcodex.com/.*/.*/.*/\(.*\)/+\1+' <<< "$i")
    page=
    page=$(wget -qO - "$i")
    comment_depths=$(grep -o 'depth-[0-9]*"' <<<$page | grep -o '[0-9]*' | tr -d "\n")
    total_comments=${#comment_depths}
    toplevel_comments=$(grep -o 1 <<<$comment_depths | wc -l)
    comments_per_thread=$(bc <<<"scale=1; $total_comments/$toplevel_comments")
    longest_thread=0
    longest_thread=$(sed 's/1/\n1/g' <<<$comment_depths | {
        while read thread; do
            thread_length=${#thread}
            if [[ $thread_length -ge $longest_thread ]] ; then
                longest_thread=$thread_length
            fi
        done
        echo $longest_thread
    })
    echo $filename $total_comments $toplevel_comments $comments_per_thread $longest_thread
done