// more code here to get dirs (string[])

    foreach(entry; parallel(dirs))
    {
        if (entry.exists)
        {
            if (entry.isDir)
                gitPull(entry);
        }
        else
            writefln("Warning: %s does not exist.\n", entry);
    }

    writeln("Done.");
}

/// Pulls from git in the given directory and displays the output in stdout.
void gitPull(string dirName)
{
    auto pid = executeShell("git pull", null, Config.none, size_t.max, dirName);
    writeln("== ", dirName, " ==\n", pid.output);
}