The RUST_LOG_STYLE variable sets the style of printed records. It has three variants:

• auto: Tries to use the style characters
• always: Always uses the style characters
• never: Turns off the style characters

See the following example:

RUST_LOG_STYLE=auto cargo run

I recommend that you use the never value if you redirect the stderr output a file or if you want to use grep or awk to extract values with special patterns.