When Gary Kildall created CP/M, he was inspired by some of the command line interface conventions used in DEC's RT-11 operating system.
wˌɛn ɡˈæɹi kɪldˈɔːl kɹiːˈeɪɾᵻd sˌiːpˈiː slˈæʃ ˈɛm, hiː wʌz ɪnspˈaɪɚd baɪ sˌʌm ʌvðə kəmˈænd lˈaɪn ˈɪntɚfˌeɪs kənvˈɛnʃənz jˈuːzd ɪn dˌiːˌiːsˈiːz ˌɑːɹtˈiː ɪlˈɛvən ˈɑːpɚɹˌeɪɾɪŋ sˈɪstəm.