“A widget for running scripts in the Today View in OS X Yosemite’s Notification Center”

Here a nice list of sample uses
Wiki
Reddit 1
Reddit 2

Example of colorized memory display

ps xmo rss=,pmem=,comm= | while read rss pmem comm; ((n++<5)); do
 
    size="$[rss/1024]";
    short=$[4-${#size}];
    size="(${size}M)";
    i=0;
    while ((i++ < short)); do size=" $size"; done;
 
    pmem="${pmem%%.*}"
    if   (($pmem >= 20)); then color=$'\e[31m';
    elif (($pmem >= 10)); then color=$'\e[33m';
    else                       color=$'\e[32m ';
    fi;
 
    echo "$color$pmem% $size $(basename "$comm")"$'\e[0m'"";
done

ps xmo rss=,pmem=,comm= | while read rss pmem comm; ((n++<5)); do

size="$[rss/1024]";

short=$[4-${#size}];

size="(${size}M)";

i=0;

while ((i++ < short)); do size=" $size"; done;

pmem="${pmem%%.*}"

if (($pmem >= 20)); then color=$'\e[31m';

elif (($pmem >= 10)); then color=$'\e[33m';

else color=$'\e[32m ';

fi;

echo "$color$pmem% $size $(basename "$comm")"$'\e[0m'"";

done

Today-Scripts – A widget for running scripts in the Today View in OS X Yosemite’s Notification Center

Alexander