A digression on echo. - Other *nix-like OSes & POSIX related
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After commenting on this thread I remembered a text on echo that Brian Kernighan and Rob Pike wrote in their book The UNIX Programming Environment called A digression on echo.
The single option -n is not like other options in other utilities. For example, while most utilities use getopt(3) to get the options, echo(1) should not use it, since a gotten option could be an argument to be echoed. See how OpenBSD implement echo, for example: Code: #include <stdio.h> Other than -n, modern echo implementations also add a new complexity: the C-like backslash sequences like '\n' and '\t'. Some echo implementations (such as OpenBSD's) just ignore them, but some (such as Bash built-in) don't. Here is another digression on echo about this very topic, by Doug Mcllroy, best known for proposing the UNIX pipelines and creating several UNIX tools: There is, however, another utility that does not print newlines when not asked for and that does interpret C-like backslash sequences: printf(1) PS: I don't know the right forum to post it. I posted it here in the Philosophy forum since I think that the question on bloatedness and feature creep are related to UNIX Philosophy. |
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Messages In This Thread |
A digression on echo. - by seninha - 20-04-2020, 10:57 AM
RE: A digression on echo. - by jkl - 20-04-2020, 03:31 PM
RE: A digression on echo. - by z3bra - 20-04-2020, 03:40 PM
RE: A digression on echo. - by seninha - 20-04-2020, 04:29 PM
RE: A digression on echo. - by jkl - 20-04-2020, 04:33 PM
RE: A digression on echo. - by z3bra - 21-04-2020, 05:09 AM
RE: A digression on echo. - by jkl - 21-04-2020, 05:13 AM
RE: A digression on echo. - by twee - 21-04-2020, 05:22 PM
RE: A digression on echo. - by seninha - 28-11-2020, 11:23 AM
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