grub: debug
15.1.9 debug
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This variable may be set to enable debugging output from various
components of GRUB. The value is an ordered list of debug facility names
separated by whitespace or ‘,’. If the special facility named ‘all’ is
present then debugging output of all facility names is enabled at the
start of processing the value of this variable. A facility's debug
output can then be disabled by prefixing its name with a ‘-’. The last
occurence facility name with or without a leading ‘-’ takes precendent
over any previous occurence. This allows the easy enabling or disabling
of facilities by appending a ‘,’ and then the facility name with or
without the leading ‘-’, which will preserve the state of the rest of
the facilities. The facility names are the first argument to
grub_dprintf. Consult the source for more details.
Info Catalog
grub: config_file
grub: Special environment variables
grub: default