Comment by avadodin
1 day ago
iirc they were initially using actual ttys(as in typewriters) and the input delay was hell which is the reason so many UNIX commands are two letters.
So likely they would work on the printout:
1,$n
And then input the corrections into ed(1).
That was one generation before this. In unix v4 times, input latency was in the order of ~100ms, basically limited by the serial port.
Pretty advanced terminals were starting to show up too - https://en.wikipedia.org/wiki/VT100