Easy words to type on a cellphone

My coworker was wondering the other day what words he could type out on a cell phone without pressing a button more than once in a row. That is to say, what English words are formed using only the first letter on a phone button. It turns out this is an incredibly simple question to answer with a little bit of command line knowledge. If you want to do this for yourself on a list of words, say the German dictionary, just find open a Linux terminal and put in

egrep ^[adgjmptw]+$ words >> cellphonewords

where "words" is your wordlist and "cellphonewords" is your output file.

Without further ado, the list:
a
ad
adapt
add
am
amp
apt
at
d
dad
dam
damp
data
g
gad
gag
gamma
gap
j
jag
jam
jaw
m
ma
mad
madam
magma
mama
mamma
map
mat
matt
maw
p
pa
pad
pap
papa
papaw
pat
paw
pawpaw
t
tad
tag
tam
tamp
tap
tat
w
wad
wag
watt