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When used with no arguments displays all available text output modes. The set mode determines the columns and rows of the text display when in text mode. An asterisk, ‘*’, will be at the end of the line of the currently set mode.
If given a single parameter, it must be ‘min’, ‘max’, or a mode number given by the listing when run with no arguments. These arguments set the mode to the minimum, maximum, and particular mode respectively.
Otherwise, the command must be given two numerical arguments specifying the columns and rows of the desired mode. Specifying a columns and rows combination that corresponds to no supported mode, will return error, but otherwise have no effect.
By default GRUB will start in whatever mode the EFI firmware defaults to. There are firmwares known to set up the default mode such that output behaves strangely, for example the cursor in the GRUB shell never reaches the bottom of the screen or, when typing characters at the prompt, characters from previous command output are overwritten. Setting the mode may fix this.
The EFI specification says that mode 0 must be available and have columns and rows of 80 and 25 respectively. Mode 1 may be defined and if so must have columns and rows of 80 and 50 respectively. Any other modes may have columns and rows arbitrarily defined by the firmware. This means that a mode with columns and rows of 100 and 31 on one firmware may be a different mode number on a different firmware or not exist at all. Likewise, mode number 2 on one firmware may have a different number of columns and rows than mode 2 on a different firmware. So one should not rely on a particular mode number or a mode of a certain number of columns and rows existing on all firmwares, except for mode 0.
Note: This command is only available on EFI platforms and is similar to EFI shell "mode" command.
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