redirect.zig

const std = @import("std");
const c = std.c;
const fs = std.fs;
const Child = std.process.Child;

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const allocator = gpa.allocator();
    const fd = try fs.cwd().createFile("hoge", .{});
    defer {
        fd.close();
        _ = gpa.deinit();
    }

    _ = c.close(1); // close stdout
    _ = c.dup(@as(c.fd_t, @intCast(fd.handle)));

    const command = [_][]const u8{"cat"};
    var child = Child.init(&command, allocator);
    try child.spawn();
    const res = try child.wait();

    std.debug.print("{!}\n", .{res});
}