\c  A counter that increments for each statement you issue
\D  The full current date
\d The default database
\h The server host
\l The current delimiter (new in 5.1.12)
\m  Minutes of the current time
\n  A newline character
\O  The current month in three-letter format (Jan, Feb, …)
\o  The current month in numeric format
\P  am/pm
\p The current TCP/IP port or socket file
\R  The current time, in 24-hour military time (0–23)
\r  The current time, standard 12-hour time (1–12)
\S  Semicolon
\s  Seconds of the current time
\t  A tab character

MySQL -u root -p root --prompt \h //此处h之前应为反斜线