mtools: exit codes
2.8 Exit codes
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All the Mtools commands return 0 on success, 1 on utter failure, or 2
on partial failure. All the Mtools commands perform a few sanity
checks before going ahead, to make sure that the disk is indeed an
MS-DOS disk (as opposed to, say an ext2 or MINIX disk). These checks
may reject partially corrupted disks, which might otherwise still be
readable. To avoid these checks, set the MTOOLS_SKIP_CHECK
environmental variable or the corresponding configuration file variable
(global variables)