diff --git a/README.md b/README.md
index e90af38..9784ddb 100644
--- a/README.md
+++ b/README.md
@@ -5,8 +5,6 @@ rga is a tool to recursively search for text in many different types of files. I
 [![Linux build status](https://travis-ci.org/phiresky/ripgrep_all.svg)](https://travis-ci.org/BurntSushi/ripgrep)
 [![Crates.io](https://img.shields.io/crates/v/ripgrep_all.svg)](https://crates.io/crates/ripgrep_all)
 
-similar:
-
 # todo
 
 - jpg adapter (based on object classification / detection (yolo?)) for fun
diff --git a/src/adapters.rs b/src/adapters.rs
index c75f969..cdcc6ce 100644
--- a/src/adapters.rs
+++ b/src/adapters.rs
@@ -11,7 +11,7 @@ use crate::matching::*;
 use crate::preproc::PreprocConfig;
 use failure::*;
 use log::*;
-use regex::{Regex, RegexSet};
+use regex::{Regex};
 use std::borrow::Cow;
 use std::collections::HashMap;
 use std::io::prelude::*;
diff --git a/src/adapters/pdfpages.rs b/src/adapters/pdfpages.rs
index 0705935..52912a9 100644
--- a/src/adapters/pdfpages.rs
+++ b/src/adapters/pdfpages.rs
@@ -1,16 +1,16 @@
 use super::*;
 use crate::adapters::spawning::map_exe_error;
-use crate::adapters::spawning::pipe_output;
+
 use crate::preproc::rga_preproc;
 use lazy_static::lazy_static;
-use spawning::SpawningFileAdapter;
+
 use std::fs::File;
 use std::io::BufReader;
-use std::io::Cursor;
-use std::io::Take;
+
+
 use std::path::PathBuf;
 use std::process::Command;
-use std::process::Stdio;
+
 
 static EXTENSIONS: &[&str] = &["pdf"];
 
@@ -46,7 +46,7 @@ impl FileAdapter for PdfPagesAdapter {
 		let AdaptInfo {
 			filepath_hint,
 			is_real_file,
-			mut inp,
+			inp: _,
 			oup,
 			line_prefix,
 			archive_recursion_depth,
diff --git a/src/args.rs b/src/args.rs
index 868f45d..c63f847 100644
--- a/src/args.rs
+++ b/src/args.rs
@@ -32,35 +32,46 @@ set_default!(max_archive_recursion, 4, i32);
 #[structopt(rename_all = "kebab-case", set_term_width = 80)]
 pub struct RgaArgs {
     #[serde(default, skip_serializing_if = "is_default")]
-    #[structopt(long = "--rga-no-cache", help = "Disable caching of results")]
+    #[structopt(long = "--rga-no-cache")]
+    /// Disable caching of results
+    ///
+    /// By default, rga caches the extracted text to a database in ~/.cache/rga if it is small enough.
+    /// This way, repeated searches on the same set of files will be much faster.
+    /// If you pass this flag, all caching will be disabled.
     pub no_cache: bool,
 
     #[serde(default, skip_serializing_if = "is_default")]
-    #[structopt(
-        long = "--rga-accurate",
-        help = "Use more accurate but slower matching by mime type"
-    )]
+    #[structopt(long = "--rga-accurate")]
+    /// Use more accurate but slower matching by mime type
+    ///
+    /// By default, rga will match files using file extensions.
+    /// Some programs, such as sqlite3, don't care about the file extension at all,
+    /// so users sometimes use any or no extension at all. With this flag, rga
+    /// will try to detect the mime type of input files using the magic bytes
+    /// (similar to the `file` utility), and use that to choose the adapter.
     pub accurate: bool,
 
     #[serde(default, skip_serializing_if = "is_default")]
     #[structopt(
         long = "--rga-adapters",
         require_equals = true,
-        require_delimiter = true,
-        help = "Change which adapters to use and in which priority order (descending)"
+        require_delimiter = true
     )]
+    /// Change which adapters to use and in which priority order (descending)
+    ///
+    /// "foo,bar" means use only adapters foo and bar.
+    /// "-bar,baz" means use all default adapters except for bar and baz.
+    /// "+bar,baz" means use all default adapters and also bar and baz.
     pub adapters: Vec<String>,
 
     #[serde(
         default = "def_cache_max_blob_len",
         skip_serializing_if = "def_cache_max_blob_len_if"
     )]
-    #[structopt(
-        long = "--rga-cache-max-blob-len",
-        default_value = "2000000",
-        help = "Max compressed size to cache",
-        long_help = "Longest byte length (after compression) to store in cache. Longer adapter outputs will not be cached and recomputed every time."
-    )]
+    #[structopt(long = "--rga-cache-max-blob-len", default_value = "2000000")]
+    /// Max compressed size to cache
+    ///
+    /// Longest byte length (after compression) to store in cache. Longer adapter outputs will not be cached and recomputed every time.
     pub cache_max_blob_len: u32,
 
     #[serde(
@@ -69,10 +80,12 @@ pub struct RgaArgs {
     )]
     #[structopt(
         long = "--rga-cache-compression-level",
+        hidden_short_help = true,
         default_value = "12",
         require_equals = true,
-        help = "ZSTD compression level to apply to adapter outputs before storing in cache db"
+        help = ""
     )]
+    /// ZSTD compression level to apply to adapter outputs before storing in cache db
     pub cache_compression_level: u32,
 
     #[serde(
diff --git a/src/bin/rga-preproc.rs b/src/bin/rga-preproc.rs
index d323e29..ae586f3 100644
--- a/src/bin/rga-preproc.rs
+++ b/src/bin/rga-preproc.rs
@@ -1,4 +1,4 @@
-use failure::{format_err, Fallible};
+use failure::{Fallible};
 use rga::adapters::*;
 use rga::preproc::*;
 use ripgrep_all as rga;
diff --git a/src/bin/rga.rs b/src/bin/rga.rs
index 1324a70..64c7923 100644
--- a/src/bin/rga.rs
+++ b/src/bin/rga.rs
@@ -35,7 +35,7 @@ fn main() -> Fallible<()> {
         for adapter in enabled_adapters {
             print(adapter)
         }
-        println!("The following adapters are disabled by default, and can be enabled using '--rga-adapters=+tesseract,xyz':\n");
+        println!("The following adapters are disabled by default, and can be enabled using '--rga-adapters=+pdfpages,tesseract':\n");
         for adapter in disabled_adapters {
             print(adapter)
         }