If no fields or global options are specified, -s has no effect. GNU sort has no limits on input line length or restric- silently supplies one. The following options affect the ordering of output lines. They may be specified globally or as part of a specific key field. Ignore leading blanks when finding sort keys in each line.
Invalid names compare low to valid names.
Compare according to arithmetic value an initial numeric string consisting of optional white space, an optional - sign, and zero or more digits, optionally followed by a decimal point and zero or more digits. Reverse the result of comparison, so that lines with greater key values appear earlier in the out- put instead of later. Use character separator as the field separator when finding the sort keys in each line. The field separator is not considered to be part of either the field preceding or the field following it. For the default case or the -m option, only output the first of a sequence of lines that compare equal.