cyclenext is a shell script to monitor a specific taskwarrior (http://taskwarrior.org/) filter continuously. See https://github.com/0x6d64/cyclenext for improved python version

cyclenext

#!/bin/sh
# Martin Demling, 2013
# [email protected]
# cyclenext is a script to monitor a specific taskwarrior
# (http://taskwarrior.org/) view continuously
# the script was developed on an OSX 10.7.5 system, but should run on other
# UNIX platforms
# usage: cyclenext <filter>
TASKFILE="/Users/martindemling/taskdir/undo.data"

# trigger redraw if size of terminal window changes 
trap 'redraw $*' WINCH 

# returns age of file in seconds
filemodifiedseconds()
{
  local OLD=`stat -f %m $1`;
	local NOW=`date +%s`;
	(( DIFF = (NOW - OLD) ));
	echo $DIFF
}

# returns age of file in minutes
filemodifiedminutes()
{
	local OLD=`stat -f %m $1`;
	local NOW=`date +%s`;
	(( DIFF = (NOW - OLD) ));
	let DIFF=$DIFF/60;
	echo $DIFF
}

# detects how many lines the terminal can currently display, limit the output
# accordingly. The number 15 was found by trial, you may have to increase/
# decrease based on how many of your tasks need more than one line (due to
# line wrapping)
linestodisplay()
{
	lines=$(tput lines)
	#columns=$(tput cols)
	(( LINESTODISPLAY = ($lines - 15) ))
	echo $LINESTODISPLAY
}

draw()
{
	clear
	local AGE=$(filemodifiedminutes $TASKFILE)
	echo "last change: $AGE minutes ago"
	task $* rc.gc=off limit:$(linestodisplay) 
}

redraw()
{
	sleep 1
	draw $*
}
#---------
# main loop
if [ "$#" = "0" ]
then
	echo "no task filter given!"
	echo "usage: cyclenext <filter>"
else
	DELAY=2
	for ((;;)) do
		draw $*
		#sleep $DELAY
		sleep 1;
		# check file every $DELAY seconds, draw if change is detected,
		# if 5 minutes (150*2secs) pass without change, draw regardless:
		# this will be useful to reflect changes in the config files (which
		# are not monitored otherwise
		for (( c=1; c<=150; c++ ))
			do
				AGE=$(filemodifiedseconds $TASKFILE)
				if [ $AGE -gt $DELAY ]
				then
					sleep $DELAY
				else
					sleep 1
					break
				fi
			done
	done
fi

Read my blogpost for a description, and feel free to comment!

See improved python version here: https://github.com/0x6d64/cyclenext