empty history detected as expected first history command detected as expected invalid attempt at multiple history commands detected history function explicit search succeeded history function implicit search succeeded history function implicit search with timestamps succeeded history function explicit exact search 'echo goodbye' succeeded history function explicit exact search 'echo hello' succeeded history function explicit exact search 'echo hell' succeeded history function explicit exact delete 'echo hello' succeeded history function explicit prefix delete 'echo hello' succeeded history function explicit exact search 'echo hello again' succeeded history function explicit exact search 'echo hello AGAIN' failed to find the entry