The "log" does not output anything to the console, but the "log_err" outputs.

[dmitriy-bodroff]

OS: Linux/Ubuntu.

The log does not output anything to the console, but the log_err outputs. Following the documentation, I set the RUST_LOG environment variable as:

$ export RUST_LOG=main,std::io

But log does not write to the console still.

$ ./hello
$

hello.rs

fn main() {
  log "Hello World";
}

For log_err it works:

fn main() {
  log_err "Hello World";
}

$ ./hello
rt: ---
rt: a296:main:main:                   rust: Hello World
$

[marijnh]

It seems someone updated the code to use the filename as the top-level module scope for log tags if no crate name is defined through the metadata system. So in your case, you need to use RUST_LOG=hello, rather than main. I'll update the wiki.