Hello, Le ven. 27 mai 2022 à 20:45, Greg Reagle <l...@speedpost.net> a écrit : > > I have a file named "out" (from ii) that I want to view. Of course, it can > grow while I am viewing it. I can view it with "tail -f out" or "less +F > out", both of which work. I also want to apply some processing in a > pipeline, something like "tail -f out | tr a A | less" but that does not > work. The less command ignores my keystrokes (unless I hit Ctrl-C, but that > kills tail and tr). The "tr a A" command is arbitrary; you can substitute > whatever processing you want, even just cat. > > This command "tail -f out | tr a A" is functional and has no bugs, but it > doesn't let me use the power of less, which I crave. > > This command "tail out | tr a A | less" is functional and has no bugs, but it > doesn't let me see newly appended lines. > > Can I use the power of the Unix pipeline to do text processing and the power > of less for excellent paging and still be able to see new lines as they are > appended? Why doesn't or can't less continue to monitor stdin from the > pipeline and respond to my keystrokes from the tty? > > I am using Debian 11 in case it matters, with fish. But I am happy to try > other shells. In fact I already have and that doesn't seem to help. I have > also tried more, most, nano -, and vi -, instead of less, to no avail. >
The simplest solution to avoid the side effect of killing tail and tr when using ^C to quit "follow mode" in less is to redirect the output of tr to another file, and use less +F to open that file. Like so: tail -f out | tr a A >out2 & less +F out2 Some other solutions: https://unix.stackexchange.com/a/659175 Best, AN
