Basic reminder about Sed command

(Small thing you always know, but always forget)

if you have a file "pp.txt" with the following text:

GGATSGSFFSTSTYYSGHGSSYSHSUSUSH

in order to substitute a "Y" for a "P", the command should be:

sed s/Y/P/g < ppp.txt

the substituted string will go to the standard output. I you wish, you can redirect it to a file:

sed s/Y/P/g < ppp.txt > new_ppp.txt