Random832 <random832(a)fastmail.com> wrote: |On Wed, Oct 18, 2017, at 19:03, Doug McIlroy wrote: |>> But mind you, in preparation of this email i found a bug in |>> Busybox sed(1) which simply echoes nothing for the above. |> |> I assume that * is a typo for - . If so, sed did just what |> -n tells it to--no printing except as called for by p or P. | |Or, you know, l (the letter ell). Which busybox sed appears to not |support at all, rather than somehow misapplying -n to it. The letter l, yes. But it does not fail either, so it knows about it, talking version 1.27.something here. --steffen | |Der Kragenbaer, The moon bear, |der holt sich munter he cheerfully and one by one |einen nach dem anderen runter wa.ks himself off |(By Robert Gernhardt)

Good evening everybody. Random832 <random832(a)fastmail.com> wrote: |On Thu, Oct 19, 2017, at 10:33, Steffen Nurpmeso wrote: |> Random832 <random832(a)fastmail.com> wrote: |>|On Wed, Oct 18, 2017, at 19:03, Doug McIlroy wrote: |>|>> But mind you, in preparation of this email i found a bug in |>|>> Busybox sed(1) which simply echoes nothing for the above. |>|> |>|> I assume that * is a typo for - . If so, sed did just what |>|> -n tells it to--no printing except as called for by p or P. |>| |>|Or, you know, l (the letter ell). Which busybox sed appears to not |>|support at all, rather than somehow misapplying -n to it. |> |> The letter l, yes. But it does not fail either, so it knows about |> it, talking version 1.27.something here. | |If you look at the source, it is in the list that is checked for |printing (or not) the 'unsupported command' error message, but there is |no actual code to handle it (and when called *without* -n, it just falls |through and prints once, just like if you'd had no command at all) | |https://git.busybox.net/busybox/plain/editors/sed.c?h=1_3_stable That is true. |I think that makes this a legitimate bug in busybox, rather than simply |an artifact of being a minimal tool that doesn't aim for posix (or |historical unix) conformance. Yes, it should error out or implement the stuff i think. The way it is is not handable. The comments in coreutils/cat.c are postable in this thread too: /* Rob had "cat -v" implemented as a separate applet, catv. [That is Rob AT Landley DOT NET] * See "cat -v considered harmful" at * http://cm.bell-labs.com/cm/cs/doc/84/kp.ps.gz [This server has been killed] * From USENIX Summer Conference Proceedings, 1983 * """ * The talk reviews reasons for UNIX's popularity and shows, using UCB cat * as a primary example, how UNIX has grown fat. cat isn't for printing * files with line numbers, it isn't for compressing multiple blank lines, * it's not for looking at non-printing ASCII characters, it's for * concatenating files. * We are reminded that ls isn't the place for code to break a single column * into multiple ones, and that mailnews shouldn't have its own more * processing or joke encryption code. * """ * * I agree with the argument. Unfortunately, this ship has sailed (1983...). * There are dozens of Linux distros and each of them has "cat" which supports -v. * It's unrealistic for us to "reeducate" them to use our, incompatible way * to achieve "cat -v" effect. The actual effect would be "users pissed off * by gratuitous incompatibility". And, indeed sailing (-vet explicitly compiled in): ?0[steffen@essex busybox.git]$ echo −e | cat -vet M-bM-^HM-^Re$ Then again, you know, i personally have problems with -vet and think the POSIX sed variant is easier to grasp: ?0[steffen@essex busybox.git]$ echo −e | sed -n l \342\210\222e$ --steffen | |Der Kragenbaer, The moon bear, |der holt sich munter he cheerfully and one by one |einen nach dem anderen runter wa.ks himself off |(By Robert Gernhardt)