$ java -version
openjdk version "12" 2019-03-19
OpenJDK Runtime Environment (build 12+33-2)
OpenJDK 64-Bit Server VM (build 12+33-2, mixed mode)
$ uname -a
FreeBSD freebsd 12.0-RELEASE FreeBSD 12.0-RELEASE r341666 GENERIC  amd64

I've developed a suite of micro services for Linux in 2016 and it worked perfectly with Foundation and IBM Kitura frameworks.

In 2017 we deployed the micro services and the performance has been great specially at the level of RAM, which is very important for us as we need it to run on expensive ECC RAM servers.

So yes, you can use Swift as a general purpose programming language on Linux as you can on macOS, and I recommend it.

i586-pc-msdosdjgpp-gcc -v
Using built-in specs.
COLLECT_GCC=i586-pc-msdosdjgpp-gcc
COLLECT_LTO_WRAPPER=/usr/local/djgpp/libexec/gcc/i586-pc-msdosdjgpp/8.2.0/lto-wrapper
Target: i586-pc-msdosdjgpp
Configured with: ../gnu/gcc-8.20/configure --target=i586-pc-msdosdjgpp --program-prefix=i586-pc-msdosdjgpp- --prefix=/usr/local/djgpp --disable-nls --disable-plugin --disable-lto --enable-lto --enable-libstdcxx-filesystem-ts --enable-libquadmath-support --with-gmp=/home/fsb4000/github/build-djgpp/build/djcross-gcc-8.2.0/tmpinst --with-mpfr=/home/fsb4000/github/build-djgpp/build/djcross-gcc-8.2.0/tmpinst --with-mpc=/home/fsb4000/github/build-djgpp/build/djcross-gcc-8.2.0/tmpinst --enable-version-specific-runtime-libs --enable-languages=c,c++
Thread model: single
gcc version 8.2.0 (GCC) 

Describing JavaAcceptanceTests
  [+] single solution 338ms
  [+] no solution 322ms
  [+] many solutions 343ms
  [+] single solution complex numbers 355ms
  [+] no output without -verbose 310ms

Describing TypescriptAcceptanceTests
  [+] single solution 205ms
  [+] no solution 183ms
  [+] many solutions 205ms
  [+] single solution complex numbers 242ms
  [+] no output without -verbose 180ms

java -version
java version "11.0.1" 2018-10-16 LTS
Java(TM) SE Runtime Environment 18.9 (build 11.0.1+13-LTS)
Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.1+13-LTS, mixed mode)

node --version
v8.11.1

$ zypper repos --uri
Repository priorities are without effect. All enabled repositories share the same priority.

# | Alias      | Name       | Enabled | GPG Check | Refresh | URI
--+------------+------------+---------+-----------+---------+-------------------------------------------------------------------
1 | oss        | oss        | Yes     | (r ) Yes  | No      | http://download.opensuse.org/distribution/leap/42.3/repo/oss/suse/
2 | oss_update | oss_update | Yes     | (r ) Yes  | No      | http://download.opensuse.org/update/leap/42.3/oss/

$ sudo zypper refresh
Repository 'oss' is up to date.
Retrieving repository 'oss_update' metadata ...............................................................................................................[done]
All repositories have been refreshed.

$ sudo zypper install gcc7
Loading repository data...
Reading installed packages...
'gcc7' is already installed.
No update candidate for 'gcc7-7.2.1+r253435-3.2.x86_64'. The highest available version is already installed.
Resolving package dependencies...

Nothing to do.

$ sudo zypper up
Loading repository data...
Reading installed packages...

Nothing to do.

$ sudo zypper dup
Warning: You are about to do a distribution upgrade with all enabled repositories. 
Make sure these repositories are compatible before you continue.
See 'man zypper' for more information about this command.
Loading repository data...
Reading installed packages...
Computing distribution upgrade...

Nothing to do.

Погуглил структуру блокчейна и транзакций. Не увидел места куда можно вставить проивольные данные.
Плохо искал?

Структура доклада: 
1. Программисты в таком кол-ве и качестве больше не нужны. 
С развитием техники и кухарки научились автоматизировать процессы. 

2. ББС: Так, сейчас я отвечу, можно ? Аллё... 
   БЕБ: Привет, я на Середниковской. 
   ББС: Ну жду тебя, жду... 
   БЕБ: Как дела ? Чё (прим. авт - произ. от устар "что") там делаешь ? 
   ББС: Пишу видео - рассказываю как раз про программистов. 
   БЕБ: Ну давай... 
   ББС: Спасибо ! 
   ББС: Извините пожалуйста, что отвлёкся... 

3. "Вышли деньги, или Деньги - вышли"... 

4. Троллинг материлистов тезисом: "Человек - это материя, которая догадалась что она есть". Отсыл к больцмановскому мозгу.

static int greater (void* a, void* b)
{
    int arg1 = * (int*)a;
    int arg2 = * (int*)b;

    if (arg1 < arg2) return 1;
    if (arg1 > arg2) return -1;
    return 0;
}

void some_func(int[] copy_input)
{
    Posix.qsort(copy_input, copy_input.length, sizeof(int), greater);
    ....
}

static int greater_int (int arg1, int arg2)
{
    if (arg1 < arg2) return 1;
    if (arg1 > arg2) return -1;
    return 0;
}
void some_func(int[] copy_input)
{
    qsort_with_data<int>(copy_input, sizeof(int), greater_int);
    ....
}

/usr/share/vala-0.36/vapi/glib-2.0.vapi:5714:11: runtime error: load of misaligned address 0x60200000ea74 for type 'const <unknown> *', which requires 8 byte alignment
0x60200000ea74: note: pointer points here
  0e 00 00 00 0e 00 00 00  0e 00 00 00 0e 00 00 00  03 00 00 00 00 00 00 02  10 00 00 00 01 00 00 54
              ^ 
/usr/share/vala-0.36/vapi/glib-2.0.vapi:5714:11: runtime error: load of misaligned address 0x60200000ea74 for type 'const <unknown> *', which requires 8 byte alignment
0x60200000ea74: note: pointer points here
  0e 00 00 00 0e 00 00 00  0e 00 00 00 0e 00 00 00  03 00 00 00 00 00 00 02  10 00 00 00 01 00 00 54

gcc version 7.2.0 (Ubuntu 7.2.0-1ubuntu1~16.04)
Vala 0.36.8

const char* noexcept_thrower_c(int i)
{
    if (i == 0)
        return "error";
    return NULL;
}

int noexcept_try(int i)
{
    int res;
    if (noexcept_thrower_c(i) == NULL)
    {
        res = 0;
    }
    else
    {
        res = 1;
    }
    return res;
}

void thrower_cpp(int i)
{
    if (i == 0)
        throw std::runtime_error("error");
}

int cpp_try(int i)
{
    int res;
    try
    {
        thrower_cpp(i);
        res = 0;
    }
    catch(const std::exception&)
    {
        res = 1;
    }
    return res;
}

void thrower_c(int i)
{
    if (i == 0)
        Throw("error");
}

int cexception_try(int i)
{
    int res;
    CEXCEPTION_T e = CEXCEPTION_NONE;
    Try
    {
        thrower_c(i);
        res = 0;
    }
    Catch(e)
    {
        (void)e;
        res = 1;
    }
    return res;
}

public errordomain Error
{
    Thrower,
}

void thrower(int i)  throws Error
{
    if (i == 0)
        throw new Error.Thrower ("error");
}

int vala_try(int i)
{
    int res;
    try
    {
        thrower(i);
        res = 0;
    }
    catch(Error e)
    {
        (void)e;
        res = 1;
    }
    return res;
}

vala_try                                 3 ns/op
vala_catch                             252 ns/op
c++_try                                  1 ns/op
c++_catch                             2382 ns/op
noexcept_try                             1 ns/op
noexcept_catch                           1 ns/op
сexception_try                           9 ns/op
сexception_catch                        25 ns/op

-fstack-protector-all --param ssp-buffer-size=4 -fstack-check

/GS

-Wl,--nxcompat

/NXCOMPAT

-Wl,--dynamicbase

/DYNAMICBASE

-Wl,--high-entropy-va

/HIGHENTROPYVA

/guard:cf