Commodore PC 20 - Page 173

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The errors are then sent to the specified file. Remember, though,
not to use the If switch when you redirect chkdsk output.
If chkdsk finds errors on the disk in drive A and you want to try
to correct them, type the following command:
chkdsk a: If
Chkdsk now tries to correct any errors it encounters on the disk
in
drive A.
MS-DOS Commands 35