Re: [TUHS] Unix taste

Doug McIlroy: The single-token rule meant that, if you wanted to supply an option to wc in the pipeline ls > wc > you couldn't write ls > wc -l > as one would expect, but instead had to write ls > "wc -l" > Yet a quoted "wc -l" as a bare command or (I suspect) as the first command in a pipeline would lead to "command not found". What a mess! ====== Then as now, a quoted "wc -l" would be taken by the shell to be a single world, so "wc -l" file would be a request to find a file named "wc -l" (without the quotes but with the embedded blank) somewhere in the search path, and execute it with argv[0] = "wc -l" and argv[1] = "file". But the shell's parser bound only the word following > or < to the operator, so the command had to be quoted (if it had arguments) to make it a single word. So in the old syntax, if you needed to quote an argument of a command that was part of a pipeline but not at the head, you'd have to embed quotes within quotes; e.g. ls > "grep '[0-9]'" > Decidedly a quick hack, just like the original implementation of fork(2) (which was, approximately, swap the current process out, but keep the in-core copy, and give one of the two a new process ID and process-table entry). Though unlike the original fork, the original pipeline syntax was rough enough to be worth fixing early on. As a side note, when I was writing my earlier message, I was going to construct an example using wc -l, until I checked the manual and discovered that when pipelines were invented wc didn't yet take options. I also thought about an example using grep, except grep hadn't appeared yet either. Pipelines (especially once they were attractive and convenient to use) made a bigger difference than we remember in how commands worked and which commands were useful. And of course Doug gets at least as much credit as Ken for changing our lives with all that. Norman Wilson Toronto ON