I really wish people would give Fortran a second chance. It has come a long way from the ancient, all-caps days.
Even in F08 there's a lot of backwards-compatibility cruft still left in the language, too. The IO model still provides very little abstraction and is based on tape drives. You can/have to "rewind" files. There are obscure "unit descriptors" that manifest themselves as integer literals in most code posted online which makes it a chore to learn from. As far as I can tell there is no functionality that approximates the behaviour of C++'s streams.
It's fast as hell, and the GNU compiler is mature and well-developed, but Fortran remains a horrid language for doing any sort of interactive programming. It's best used if you just give it some arguments, let it run free, and then have it return some object or value that a more sane language can then interpret and present to the user for a decision.
There is little reason to learn a language where the only sane choice for doing input/output involves calling your Fortran module from a python script and letting the python handle i/o.
This isn't necessarily a Fortran-specific thing. The standard C library includes a rewind(fd) function, equivalent to lseek(fd, 0, SEEK_SET).
Fortran might be used more widely, like C++ is, if it wasn't so awful for doing things other than shitting out numbers at insane speeds.
Well, you can think of a "unit descriptor" (or somewhat more Fortranny, "file unit number") as something roughly equivalent to a POSIX file descriptor, which is also an integer. The problem, as you allude to, is that classically unit numbers were assigned by the programmer rather than the OS or runtime library, so you could end up with clashes e.g. if you used two libraries which both wanted to do I/O on, say, unit=10. Modern Fortran has a solution to this, though, in the NEWUNIT= specifier, where the runtime library assigns a unique unit number.
> As far as I can tell there is no functionality that approximates the behaviour of C++'s streams.
As of Fortran 2003, there is ACCESS="stream", which is a record-less file similar to what common operating systems and programming languages nowadays provide.
> It's fast as hell, and the GNU compiler is mature and well-developed, but Fortran remains a horrid language for doing any sort of interactive programming.
Personally, I'm hoping for Julia to succeed, but we'll see..
Modern Perl is pretty nice. 90s Perl still not so good.
This is how the modern FORTRAN Hello world looks like...
program hello
print *, "Hello World!"
end program hello