[[using-shell-customization-logging]]
= Logging

On default a _Spring Boot_ application will log messages into a console which
at minimum is annoying and may also mix output from a shell commands.
Fortunately there is a simple way to instruct logging changes via boot properties.

Completely silence console logging by defining its pattern as an empty value.

[source, yaml]
----
logging:
  pattern:
    console:
----

If you need log from a shell then write those into a file.

[source, yaml]
----
logging:
  file:
    name: shell.log
----

If you need different log levels.

[source, yaml]
----
logging:
  level:
    org:
      springframework:
        shell: debug
----

Passing contiguration properties as command line options is not supported but
you can use any other ways supported by boot, for example.

[source, bash]
----
$ java -Dlogging.level.root=debug -jar demo.jar
$ LOGGING_LEVEL_ROOT=debug java -jar demo.jar
----

NOTE: In a GraalVM image settings are locked during compilation which means
      you can't change log levels at runtime.
