Shell Programming and Scripting

man sed

either this way: "sed -n '<program>' <filename>"

or that way: "cat <filename> | sed -n '<program>'"

bakunin

sed -n '/^Finished/ {
H
}
$ {
x
p
}
/^Started/,/^Finished/ {
/^Started/ {
h
}
/^Started/ !{
H
}
}' file

can you please tell in detail how is this working, i know there is only some minore changes in the above code to get the first occurrence of Started and Finished. But didn't understand the above code properly
Please help.