update readme

[Shooter3k]

Can you please update the readme to include, at the very least, the same documentation for the help that's in the code? Ideally with some examples as well

rling version: 1.74 2020/08/24 14:25:43 dlr Exp dlr $

rling - remove matching lines from a file
rling input output [remfil1 remfile2 ...]

    -i              Ignore any error/missing files on remove list
    -d              Removes duplicate lines from input (on by default)
    -D file         Write duplicates to file
    -n              Do not remove duplicate lines from input
    -c              Output lines common to input and remove files
    -s              Sort output. Default is input order.
                    This will make the -b and -f options substantially faster
    -t number       Number of threads to use
    -p prime        Force size of hash table
    -b              Use binary search vs hash (slower, but less memory)
    -2              Use rli2 mode - all files must be sorted. Low mem usage.
    -f              Use files instead of memory (slower, but small memory)
    -l [len]                Limit all matching to a specific length.
    -M memsize      Maximum memory to use for -f mode
    -T path         Directory to store temp files in
    -q [cahwl]      Do frequency analysis on input
                    a - all output, c - count, l - length, w - word,
                    s - running statistics, h - append histogram
                    Additional files will be matched against input files
    -h              This help

    stdin and stdout can be used in the place of any filename