This specifies to continue processing when one of the input files is the same as the output files.
Because the processing result is overwritten to the input file when I/O overwrite option (-v) is specified, the disk space can be saved. When this option is omitted, and the same file as the output file is specified for one of the input files, it is an error. Only when the Sort option (-s) is specified, it is enabled.
Format
-v
Note
Note that the data of the input files might not be secured when an error occurs in the sort processing.
