cleanup.sh

#! /usr/bin/env bash

set -e

# Clean up useless files
for file in *.txt; do
    [[ -f "$file" ]] || continue

    if grep "There are no student comments for this assignment" "$file" >/dev/null &&
	grep "There is no student submission text data for this assignment." "$file" >/dev/null; then
	echo "Deleting $file"
	rm "$file"
	continue
    fi
done


# Rename _attempts_
for file in *_attempt_*; do
    [[ -f "$file" ]] || continue

    newfile=$(echo "$file" | awk '{ split($0, n, "_"); split($0, e, "."); printf "%s.%s", n[2], e[length(e)] }')
    mv "$file" "$newfile"
    echo "Renaming $file to $newfile"
done

Barely tested.

Shows some good bashisms though: for example use *blah instead of $(ls *blah), and always check if the file actually exists in the loop.

Always use -e

The creation of the new filename is pretty ghettotastic though