Undocumented in source.

auto helpText = q"EOS Synopsis: tsv-sample [options] [file...] Sample input lines or randomize their order. Several modes of operation are available: * Shuffling (the default): All input lines are output in random order. All orderings are equally likely. * Random sampling (--n|num N): A random sample of N lines are selected and written to standard output. By default, selected lines are written in random order. All sample sets and orderings are equally likely. Use --i|inorder to write the selected lines in the original input order. * Weighted random sampling (--n|num N, --w|weight-field F): A weighted sample of N lines is produced. Weights are taken from field F. Lines are output in weighted selection order. Use --i|inorder to write in original input order. Omit --n|num to shuffle all lines (weighted shuffling). * Sampling with replacement (--r|replace, --n|num N): All input lines are read in, then lines are repeatedly selected at random and written out. This continues until N lines are output. Individual lines can be written multiple times. Output continues forever if N is zero or not provided. * Bernoulli sampling (--p|prob P): A random subset of lines is selected based on probability P, a 0.0-1.0 value. This is a streaming operation. A decision is made on each line as it is read. Line order is not changed. * Distinct sampling (--k|key-fields F, --p|prob P): Input lines are sampled based on the values in the key fields. A subset of keys are chosen based on the inclusion probability (a 'distinct' set of keys). All lines with one of the selected keys are output. Line order is not changed. Fields are specified using field number or field name. Field names require that the input file has a header line. Use '--help-verbose' for detailed information. Options: EOS";