A shell script to remind me of tasks that are due soon, using this system: http://wcm1.web.rice.edu/plain-text-gtd.html

duesoon.sh

#!/bin/sh

TODAY=$(date +%m)
FILE=~/.duesoon

# This may be more complex than need be, but it permits months with or without leading zeroes
let THISMO=$TODAY-0
if [ $THISMO = 12 ]; then
	let NEXTMO=01 
else
	let NEXTMO=$THISMO+1
fi
if [ $THISMO = 01 ]; then
	let LASTMO=12
else
	let LASTMO=$THISMO-1 
fi

# Empty file where matches will be stored
> "$FILE"

# Find all qq tasks where due date is this month or next month
mdfind -onlyin ~/Dropbox/notes "qq due" | while read -r line; do

# Get all matches where due date is in body of file
	grep -E "due\([0]*($THISMO|$NEXTMO|$LASTMO)+.+\)" "$line" | while read -r match; do
		DUEDATE=$(echo "$match" | grep -o '[0-9]\{1,2\}-[0-9]\{1,2\}-[0-9]\{2\}')
		echo $(expr '(' $(date -jf %m-%d-%y $DUEDATE +%s) - $(date +%s) + 86399 ')' / 86400) "days\t" "$match" >> "$FILE"
	done

# Get all matches where due date is in filename
	basename "$line" | grep -E "due\([0]*($THISMO|$NEXTMO|$LASTMO)+.+\)" | while read -r match; do
		DUEDATE=$(echo "$match" | grep -o '[0-9]\{1,2\}-[0-9]\{1,2\}-[0-9]\{2\}')
		echo $(expr '(' $(date -jf %m-%d-%y $DUEDATE +%s) - $(date +%s) + 86399 ')' / 86400) "days\t" "$match" >> "$FILE" 
	done

done

# Now print all tasks due in the next 14 days, in order 
sort -g "$FILE" | grep -E '(^[^0-9][0-9]+|^[0-9]{1}|^1[0-4]+) days'