update readme

README.md

@@ -1,12 +1,12 @@
-# umnlookup [![Release](http://github-release-version.herokuapp.com/github/acmumn/umnlookup/release.svg)](https://github.com/acmumn/umnlookup/releases) [![License](https://img.shields.io/badge/license-BSD--3-ff69b4.svg)](https://github.com/acmumn/umnlookup/blob/master/LICENSE) [![Build Status](https://travis-ci.org/acmumn/umnlookup.svg?branch=master)](https://travis-ci.org/acmumn/umnlookup)
+# umnlookup [![Release](http://github-release-version.herokuapp.com/github/acmumn/umnlookup/release.svg)](https://github.com/acmumn/umnlookup/releases) [![License](https://img.shields.io/badge/license-BSD--3-ff69b4.svg)](https://github.com/acmumn/umnlookup/blob/master/LICENSE)
 
-Command-line program to look up people from the UMN student
-directory.
+Command-line program to look up people from the UMN student directory.
 
 ## Installation
 
-Install [Haskell](https://www.haskell.org/) and [Cabal](https://www.haskell.org/cabal/).
-Use Cabal to install the following packages:
+Install [Haskell](https://www.haskell.org/)
+and [Cabal](https://www.haskell.org/cabal/). Use Cabal to install the
+following packages:
 
 ```bash
 cabal install tagsoup http scalpel-0.3.1
@@ -24,3 +24,24 @@ This will install a command `umnlookup` that you can then go run.
 
 If you're having trouble installing this, go ask Prof. Eric Van Wyk
 for help. He seems to know his way around Haskell.
+
+## Notes on output
+
+If run at the command line, `umnlookup` produces a human-readable listing
+of all the people it finds. However, if you need to use it more
+programmatically, then pipe its output somewhere, like another program
+or a file. It'll instead emit a CSV-formatted list of people, looking
+like this:
+
+```
+<NAME>,<EMAIL>,<LIST OF FIELD NAMES>,<LIST OF FIELDS VALUES>
+...
+```
+
+The first two fields are name and email address, respectively, while
+the next two are **semicolon** separated lists of fields. This is
+necessary because the amount of field-value pairs can vary based on the
+person you're looking up.
+
+Literal newlines in field values get escaped as `\n`, while literal commas
+and semicolons get escaped as `\,` and `\;`.