WordFlow

WordFlow provides several simplified command-line utilities meant to be composed with UNIX pipes. This package is part of Making With Code, a Constructionist introductory CS curriculum. Most of these utilities duplicate existing functionality of built-in shell commands, but our goal is to provide the cleanest, simplest possible interface to maximize expressivity while minimizing cognitive load for beginners.

These utilities read lines of space-separated tokens from stdin and write to stdout. Several commands have an optional position argument (default=0) specifying which token to use on each line.

Usage examples

First, get ahold of a file containing a list of words. A word list is [built in to Unix and Linux](https://en.wikipedia.org/wiki/Words_(Unix). Or here's a list you can download.

Get the 1000 most common words

$ cat words.txt | frequency | order | pluck 1 | head -n 1000

How many words contain two vowels in a row

$ cat words.txt | match "aa|ee|ii|oo|uu" | count

What's the shortest word containing all five vowels?

$ cat words.txt | match "a" | match "e" | match "i" | match "o" | match "u" | length | order | head

What are the most common ten-letter words?

$ cat words.txt | length | put 10 | equal | frequency 2 | order -r | pluck 3 | head

What's the longest word which contains no repeated letters?

$ cat words.txt | length | unique 1 | length | lessthan 0 1 -e | lessthan 1 0 -e | 

Filter

• match [pattern] [position=0]: Allows lines where the specified word matches regular expression pattern. Regular expressions often need to be in quotation marks.
• lessthan [position0=0] [position1=1] [-e --equal]: Allows lines where the number at position 0 is less than the number at position 1. When --equal, lines are also allowed when the two numbers are equal.
• equal [position0=0] [position1=1]: Allows lines where the number at position 0 is equal to the number at position 1.

Map

• put [value] Prepends the value to each line.
• length [position=0] Prepends the length of the specified word to the line.
• frequency [position=0] Prepends the frequency of the specified word (approximate number of occurrences per billion words) to the line.
• pluck [position=0] Replaces each line with the specified token.

Sort

• order [position=0] [-r --reverse] Sorts lines according to the specified token. When the specified token is a number, sorts numerically, otherwise lexically.

Reduce

• count counts the number of lines sent to stdin.