Conversation so far:
What did Phillip Sheridan do postbellum?
Philip Sheridan was promoted to lieutenant general
what did Phillip Sheridan do after becoming lieutenant general?
Philip Sheridan was sent observe and report on the Franco-Prussian War
what else was Philip Sheridan was doing in the time when he was sent observe and report on the Franco-Prussian War?
Philip Sheridan was present when Emperor Napoléon III surrendered to the Germans
what happened in the franco prussian war where Philip Sheridan was present when Emperor Napoléon III surrendered to the Germans?
The Franco-Prussian War was a conflict between the Second French Empire and the German states of the North German Confederation led by the Kingdom of Prussia.
and what did Philip Sheridan think about the surrender of napoleon III to the Germans?
it was gratifying to Phillip Sheridan following his experiences with the French in Mexico.
did Philip Sheridan have any part in the Franco-Prussian war?
Phillip Sheridan had attached himself as an observer to the victorious Prussian army
what did Phillip Sheridan do after the Franco-prusssian war?
Phillip Sheridan toured most of Europe
what else did Philip Sheridan do after touring most of Europe?
Philip Sheridan returned to the United States?
how long did Philip Sheridan live after returning to the U.S?
Phillip Sheridan lived to be 57 years old
is there anything else Philip Sheridan did after the Franco-prussian war?
On November 1, 1883, Sheridan succeeded General William T. Sherman as Commanding General of the U.S. Army

Question: how long did he serve
Self-contained rewrite: how long did Philip Sheridan serve as Commanding General of the U.S. Army?