The flags are bookmarks at a certain offset in the file that can be stored inside 'flag spaces'. A flag space is something like a namespace for flags. They are used to group flags with similar characteristics or of a certain type. Some example of flagspaces could be [i]sections, registers, symbols, search hits[/i], etc.
To create a flag just type:
> f flag_name @ offset
You can remove this flag adding '-' at the begginging of the command. Most commands accept '-' as argument-prefix as a way to delete.
> f -flag_name
To switch/create between flagspaces use the 'fs' command:
[0x4A13B8C0]> fs ; list flag spaces 00 symbols 01 imports 02 sections 03 strings 04 regs 05 maps
> fs symbols > f ; list only flags in symbols flagspace ... > fs * ; select all flagspaces
You can create two flags with the same name with 'fn' or rename them with 'fr'.
Sometimes you'll like to add some flags adding a delta base address to each of them. To do this use the command 'ff' (flag from) which is used to specify this base address. Here's an example:
[0x00000000]> f patata [0x00000000]> ? patata 0x0 ; 0d ; 0o ; 0000 0000 [0x00000000]> ff 0x100 [0x00000000]> f patata [0x00000000]> ? patata 0x100 ; 256d ; 400o ; 0000 0000 [0x00000000]> ff 0x00000100 [0x00000000]> ff 0 ; reset flag from