grep -i '^[m|c|o|t|p][o|t|e|s|y][a|r|e|t|s][a|t|r|s|c][t|e|r|l|o][s|t|e|k|r]$'
Desktop/words.txt
ceases
cerate
cercle
certes
Cesare
cesser
cesses
cessor
cestos
cyeses
coacts
coasts
coatee
coater
Coates
corals
corcle
corser
corses
corset
corsos
Cortes
Cortot
coscet
cosset
Coster
cotset
Cotter
Cottle
csects
Meares
measle
meeter
Mercer
messer
messes
messet
messor
Messrs
mestee
mester
Mestor
metals
metate
metres
metros
Metter
mettle
myases
Myrtle
mystes
morale
morals
morate
morros
mosser
mosses
mottes
mottle
mottos
oyster
ottars
peaces
Pearle
pearls
peases
Perret
perses
perter
pester
pestle
pestos
petals
petate
Petros
petter
pettle
porret
Porter
Portor
posses
posset
poster
potate
Potter
pottle
pottos
tearer
Tearle
teaser
teases
teasle
teerer
teetee
Teeter
tercer
terces
tercet
terret
terror
terser
testee
tester
testes
testor
tetter
toasts
toetoe
Torres
torret
torses
torsos
tortes
tortor
tosser
tosses
totals
totter
tottle