You can use one-line heredoc
cat <<< "This is coming from the stdin"
the above is the same as
cat <<EOF
This is coming from the stdin
EOF
or you can redirect output from a command, like
diff <(ls /bin) <(ls /usr/bin)
or you can read as
while read line
do
echo =$line=
done < some_file
or simply
echo something | read param