subprocess.cpp

This is a library that tries to bend c++ into behaving like shell for subprocess management. It is probably not wise to use it as it is, but in case you'd like to try:

If you're using subprocess, then:

To run a command and get it's return code:

int code = run(exec("cmd", "-arg"));

To run a pipe:

int code = run(echo("text") | exec("rev") | exec("tee"));

ALl the commands run in an Environment, but the default one is immutable. So to be able to save your own environmental variables you'll need to create your own Environment. The defeault Environment constructor will already fill in all the environ variables for you.:

Environment env{};
int code = env.run(exec("cat", "/proc/cpuinfo") | exec("grep", "-m", "1", "bugs") | read("bugs"));
std::cout << "Bugs: " << ${"bugs"}.get(env) << std::endl;

But this is obviously a useless use of cat, so you could replace the second line with:

int code = env.run(exec("grep", "-m", "1", "bugs") < "/proc/cpuinfo" | read("bugs"));

Your Environment will safely store your variable until you want to use it again, wherever a string might go, env var might go as well.

int code = env.run(exec("mktemp") | read("tmpfile") && echo(${"bugs"}) > ${"tmpfile"});

If your wondering what except >, >> and < file redirections is supported, than you can also use << which would correspond to <<< in bash.

int code = run(exec("tee") << "Some text to be tee'd");

And of course ${"var"} works there as well. You might have also noticed that && is supported, and obviously || is as well and they do short-circuit like they should. Besides the already introduced echo and read built-ins there is also false_ and true_ for your logical pleasure.

With all of these you should be able to create your own script:

Environment env{}:
int code = env.run(make_script(
    exec("mktemp") | read("tmpfile"),
    echo("Hello world!") > ${"tmpfile"},
    exec("tee") < ${"tmpfile"}
));