The Unix terminal driver could only use one character to erase the previous character; this could be set to BS or DEL, but not both, resulting in recurring situations of ambiguity where users had to decide depending on what terminal they were using (shells that allow line editing, such as ksh, bash, and zsh, understand both).
ðə jˈuːnɪks tˈɜːmɪnəl dɹˈaɪvɚ kʊd ˈoʊnli jˈuːz wˈʌn kˈæɹɪktɚ tʊ ᵻɹˈeɪs ðə pɹˈiːviəs kˈæɹɪktɚ; ðɪs kʊd biː sˈɛt tə bˌiːˈɛs ɔːɹ dˌiːˌiːˈɛl, bˌʌt nˌɑːt bˈoʊθ, ɹɪzˈʌltɪŋ ɪn ɹᵻkˈɜːɹɪŋ sˌɪtʃuːˈeɪʃənz ʌv ˌæmbɪɡjˈuːɪɾi wˌɛɹ jˈuːzɚz hædtə dᵻsˈaɪd dᵻpˈɛndɪŋ ˌɔn wʌt tˈɜːmɪnəl ðeɪ wɜː jˈuːzɪŋ ʃˈɛlz ðæt ɐlˈaʊ lˈaɪn ˈɛdɪɾɪŋ, sˈʌtʃ ɐz kˌeɪˌɛsˈeɪtʃ, bˈæʃ, ænd zˌiːˌɛsˈeɪtʃ, ˌʌndɚstˈænd bˈoʊθ.