FOR MPD - Skips songs you don't like. Uses a per-song score, calculated based on whether you skip the song or let it play. The only dependency is MPC, as this script is almost entirely BASH. When the next song's score is negative, the script "rolls the dice" and if the score is <= the dice roll, it will skip it when it comes on.

skipdetect.sh

#!/bin/bash

# Automatically skips songs you dont like
# Skipping a song decreases its score
# Playing it for >15 seconds increases it
# Songs are skipped randomly based on their score

# Location of database file
DBFILE=~/scripts/database

# Replaces grep -m1 -F $1 $DBFILE
# Outputs first line that matches *PATTERN
# Should be more efficient :)
search(){
	IFS=\	;
	while read -r score title; do
		[[ "$title" = "$1" ]] && echo "$score	$title" && return 0;
	done < $DBFILE
	return 1;
}

# Replacement for tr -d '[]'
sanitize(){
	echo "${1//[\[\]]/}";
}

# esoteric - remove if you're not me
echo "Loading..." > /dev/shm/mpdcurrent;

while true;
do
	SKIPNEXT=0;
	NOWPLAYING=`sanitize "$(mpc current)"`;
	[ -z "$NOWPLAYING" ] && NOWPLAYING="!!!!!!!!!!!!!!!!";
	DBLINE="$(search "$NOWPLAYING")";
	SCORE=${DBLINE%	*};
	[ -z "$SCORE" ] && SCORE=0; 

	echo "Song: $NOWPLAYING";
	echo "Score: $SCORE";

	QUEUED=`sanitize "$(mpc queued)"`;
	QUEUEDLINE="$(search "$QUEUED")";

	# If a song is queued, roll dice
        # If score <= roll, skip next song
	[ ! -z "$QUEUEDLINE" ] && [ ${QUEUEDLINE%	*} -le -$(( RANDOM % 6 )) ] &&
		SKIPNEXT=1 && echo "Skipping next: $QUEUED";

	# esoteric - remove if you're not me
	echo "$SCORE | $NOWPLAYING" > /dev/shm/mpdcurrent;

	# Count seconds until song changes
	TIME_PLAYED=$(TIMEFORMAT='%0R'; time ( mpc current --wait ) 2>&1 1>/dev/null);

	# The rest of this code runs when the song changes
	[ $SKIPNEXT = 1 ] && [ "`sanitize "$(mpc current)"`" = "$QUEUED" ] &&
		mpc next -q && continue;

	if [ $TIME_PLAYED -lt 15 ]; then
		echo "Played $NOWPLAYING for less than 15 seconds";
		NEWSCORE=$(((SCORE-1)));
	else
		echo "Played $NOWPLAYING for more than 15 seconds";
		NEWSCORE=$(((SCORE+1)));
	fi

	if [ -z "$DBLINE" ]; then
		echo "Not found in database; adding";
		echo "$NEWSCORE	$NOWPLAYING" >> $DBFILE;
	else
		echo "Updating existing database entry"
		DB="$(<$DBFILE)";
		echo "${DB/$DBLINE/$NEWSCORE	$NOWPLAYING}" > $DBFILE;
	fi;
done