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Earlier quoted context omitted.
I just learned that rustup/rustc/cargo etc. work like this too. I couldn't understand why the gentoo formula was symlinking the same binary to a bunch of aliases.
On my system, these are hardlinks (regular files with a link count >1 and the same inode) rather than symlinks, though I'm not sure why.
It is sometimes used to allow one binary to be the symlink target of hundreds of commands. Android does this for most common shell commands. Toybox and busybox are examples of such implementations. https://github.com/landley/toybox https://en.m.wikipedia.org/wiki/BusyBox
Also if you want a program to call itself, which is sometimes useful, this way lets you actually call the same program, rather than assuming the name and path.
Earlier quoted context omitted.
Also if you want a program to call itself, which is sometimes useful, this way lets you actually call the same program, rather than assuming the name and path.
You can do this without assuming the name by execing /proc/$PID/exe. Then you're not vulnerable to the argv[0] spoofing described in the article. (But of course since argv[0] does exist, you should set it properly and pass through your own argv[0] unchanged.)
Earlier quoted context omitted.
Also if you want a program to call itself, which is sometimes useful, this way lets you actually call the same program, rather than assuming the name and path.
Don't do this - if you (reliably) want the path to the current executable there is no portable way to do it, but on Linux you need to readlink /proc/self/exe and on MacOS you call _NSGetExecutablePath. I forget the API on Windows.
This lost me at "goes against modern design principles" without citing what principle(s) the author had in mind that would proscribe it.
As a result, the author has such strange, absolute positions, calling it a legacy that should be abolished (only tangentially knowing some actual use cases), or that strange quote about design principles.
Despite all the talk about security, the whole debacle that argc can be 0 (and argv[0] can be NULL), is completely left aside. This has caused actual security issues quite recently[1].
I also use argv[0] for the -h help text, to show examples how to use the command.
There is also a neat little BSD extension, also supported on a number of other Unix-like systems and GNU userspace (i.e. glibc, but also other libcs like Musl): extern char *__progname; which holds the program name without the (optional) invocation path in front of it. Basically the last path component of argv[0].
The name of something is not an intrinsic property.