much better README

README.md

@@ -1,45 +1,78 @@
 fif
 ===
-[![Crates.io](https://img.shields.io/crates/v/fif.svg?style=flat-square)](https://crates.io/crates/fif)
+[![Version](https://img.shields.io/crates/v/fif.svg?style=flat-square)](https://crates.io/crates/fif)
-[![Crates.io](https://img.shields.io/crates/l/fif.svg?style=flat-square)](https://git.bune.city/lynnesbian/fif/src/branch/master/LICENSE)
+[![License](https://img.shields.io/crates/l/fif.svg?style=flat-square)](https://git.bune.city/lynnesbian/fif/src/branch/master/LICENSE)
 ![Minimum Supported Rust Version](https://img.shields.io/badge/msrv-1.43.0-orange?style=flat-square)
 [![CI Status](https://drone.bune.city/api/badges/lynnesbian/fif/status.svg?style=flat-square)](https://drone.bune.city/lynnesbian/fif)
+[![unsafe forbidden](https://img.shields.io/badge/unsafe-forbidden-success.svg)](https://github.com/rust-secure-code/safety-dance/)
 
 A command-line tool for detecting and optionally correcting files with incorrect extensions.
 
+fif recursively scans the given directory and outputs a shell script to fix the name of any files with incorrect
+extensions. By default, fif will scan all non-hidden files in the given directory, and will ignore symlinks.
+
+As fif prints a shell script to stdout rather than acting on the files directly, you may wish to redirect its output to
+a file, e.g. `fif ~/Documents > output.sh`. You can also pipe the output directly into your shell, e.g.
+`fif ~/Documents | bash`, although this is not recommended - you should look over fif's output and verify for yourself
+that it's not doing anything that will give you a headache before running it.
+
 ## Installation
-### Default backend
+### Cargo
 ```bash
 cargo install --locked fif
 ```
 
-### Other backends
+To update, simply re-run this command, or use a tool like
-`fif` supports using [infer](https://crates.io/crates/infer) or [xdg-mime](https://crates.io/crates/xdg-mime) as its
+[cargo-update](https://github.com/nabijaczleweli/cargo-update).
-backend for looking up file types. By default, xdg-mime will be used on Linux, and infer on all other systems.
 
-xdg-mime should work on any Unixy system with [libmagic/file(1)](https://www.darwinsys.com/file/) installed, although
+#### Other backends
-I've only tested it on Linux. infer should work on any system.
+`fif` supports using [`infer`](https://crates.io/crates/infer) or [`xdg-mime`](https://crates.io/crates/xdg-mime) as its
+backend for looking up file types. By default, xdg-mime will be used on
+[*nix systems](https://en.wikipedia.org/wiki/Unix-like) (Linux, macOS, *BSD, etc.), and infer on all other systems.
+
+`xdg-mime` should work on any *nix system with [libmagic/file(1)](https://www.darwinsys.com/file/) installed, although
+I've only tested it on Linux and FreeBSD. `infer` should work on any system.
 
 You can override the default backend for your system at compile time like so:
 
 ```bash
 # xdg-mime
-cargo install --features=xdg-mime-backend
+cargo install fif --features=xdg-mime-backend
 # infer
-cargo install --features=infer-backend
+cargo install fif --features=infer-backend
+```
+
+Of the supported backends, `xdg-mime` by far supports the most file types, as it uses the excellent [Shared MIME
+Info](https://gitlab.freedesktop.org/xdg/shared-mime-info/) database, whereas `infer` uses its own baked-in database.
+However, `infer` is also faster to load, if only by a few dozen milliseconds, and has no external dependencies.
+
+#### Multithreading
+It is also possible to disable multithreading by installing without default features:
+```bash
+cargo install fif --no-default-features
 ```
 
 ## Usage
 See `fif --help` for more.
 
-### The basics
+### Logging
-The simplest way to use fif looks like this:
+By default, fif will log any warnings and/or errors encountered during execution. The verbosity of the logging can be
+modified by the `RUST_LOG` to one of: `trace`, `debug`, `info`, `warn`, `error`.
+
+For example:
+
 ```bash
-fif -E images ~/Pictures
+RUST_LOG=debug fif ~/Downloads
 ```
 
-This command will scan all of the files with extensions used by image files (.jpg, .png, etc) in your `~/Pictures`
+### The basics
-directory.
+The simplest way to use fif looks like this:
+
+```bash
+fif ~/Downloads
+```
+
+This command will scan all non-hidden files in your `~/Downloads` directory.
 
 You can also manually specify a set of extensions to use:
 
@@ -47,11 +80,26 @@ You can also manually specify a set of extensions to use:
 fif -e jpeg,jpg,zip,docx ~/Documents
 ```
 
-By default, fif will output a bash script that can be used to fix all the files it found with incorrect file extensions.
+Or a set of extensions - for example, to scan files with image extensions (jpg, png, gif, bmp...):
+
+```bash
+fif -E images ~/Pictures
+```
+
+For more information, see [the man page](https://git.bune.city/lynnesbian/fif/src/branch/master/doc/fif.1.txt)
+
+### Output
+By default, fif will output a bash script (or PowerShell script on Windows) that can be used to fix all the files it
+found with incorrect file extensions.
+
 You might find it useful to output this script to a file (rather than to stdout):
 
 ```bash
 fif -E images ~/Pictures > output.sh
 ```
 
-More coming soon!
+You can also manually specify an output format to use:
+
+```bash
+fif -O powershell ~/Documents > output.ps1
+```