They say compiled languages are inconvenient for scripting because you have to recompile your script everytime you edit it. A little program build-n-run.cpp presented in this repo solves the problem.

In bash scripts, first line always starts with "shebang" followed by name of a bash interpreter. When you run bash script, effectively bash interpreter is run and this script is passed to it as first argument.

    #!/bin/bash
    echo "Hello world!"

Same approach is used for Python scripts, Scala scripts, etc. So I did the same: file hello.cpp in this repo is normal C++ program prepended with shebang line:

    #!/usr/local/bin/build-n-run
    #include <stdio.h>
    int main() {
        puts("Hello world!");
    }

build-n-run automatically recompiles script if it was edited (by comparing source and binary modification times) and then runs it:

    $ hello.cpp
    Recompiling...    <--- first time you run your script, it's recompiled
    Hello world!

    $ hello.cpp
    Hello world!

1. Download build-n-run.cpp from this repo.

2. [Optional] Check its source code: update GCC options used to compile your scripts; remove "Recompiling..." message if it messes with our scripts' output.

3. Compile and install it. I install to /usr/local/bin, so I run this command as root. You can install it anywhere you want, just don't forget to edit path in hello.cpp's shebang line. I use gcc 7.3.0, so I explicitly link libstdc++fs.a which implements std::experimental::filesystem.

    # g++ build-n-run.cpp -lstdc++fs -o /usr/local/bin/build-n-run
   

4. Create directory for compiled scripts. Its full path must be the same as installed program's plus .compiled suffix. If that directory is shared among multiple users, grant global access to it.

    # mkdir /usr/local/bin/build-n-run.compiled
    # chmod a+rwx /usr/local/bin/build-n-run.compiled
   

That's all. Now write C++ program with shebang at first line, chmod it to be executable, and run:

    $ chmod +x hello.cpp
    $ ./hello.cpp
    Recompiling...
    Hello world!

Now let's take a look at build-n-run.compiled directory:

    $ ls /usr/local/bin/build-n-run.compiled
    home--me--tmp--hello

I downloaded hello.cpp to /home/me/tmp, and compiled binary's name reflects source's full path, slashes replaced with "--".