diff --git a/Cargo.lock b/Cargo.lock
index 669c6c0..82a0c67 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -70,9 +70,9 @@ dependencies = [
 
 [[package]]
 name = "anstyle"
-version = "1.0.7"
+version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "038dfcf04a5feb68e9c60b21c9625a54c2c0616e79b72b0fd87075a056ae1d1b"
+checksum = "862ed96ca487e809f1c8e5a8447f6ee2cf102f846893800b20cebdf541fc6bbd"
 
 [[package]]
 name = "anstyle-parse"
@@ -249,9 +249,9 @@ checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
 [[package]]
 name = "clap"
-version = "4.5.4"
+version = "4.5.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90bc066a67923782aa8515dbaea16946c5bcc5addbd668bb80af688e53e548a0"
+checksum = "40b6887a1d8685cebccf115538db5c0efe625ccac9696ad45c409d96566e910f"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -259,9 +259,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.5.2"
+version = "4.5.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae129e2e766ae0ec03484e609954119f123cc1fe650337e155d03b022f24f7b4"
+checksum = "e0c66c08ce9f0c698cbce5c0279d0bb6ac936d8674174fe48f736533b964f59e"
 dependencies = [
  "anstream",
  "anstyle",
@@ -269,11 +269,20 @@ dependencies = [
  "strsim",
 ]
 
+[[package]]
+name = "clap_complete"
+version = "4.5.54"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aad5b1b4de04fead402672b48897030eec1f3bfe1550776322f59f6d6e6a5677"
+dependencies = [
+ "clap",
+]
+
 [[package]]
 name = "clap_derive"
-version = "4.5.4"
+version = "4.5.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "528131438037fd55894f62d6e9f068b8f45ac57ffa77517819645d10aed04f64"
+checksum = "d2c7947ae4cc3d851207c1adb5b5e260ff0cca11446b1d6d1423788e442257ce"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -283,9 +292,9 @@ dependencies = [
 
 [[package]]
 name = "clap_lex"
-version = "0.7.0"
+version = "0.7.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "98cc8fbded0c607b7ba9dd60cd98df59af97e84d24e49c8557331cfc26d301ce"
+checksum = "b94f61472cee1439c0b966b47e3aca9ae07e45d070759512cd390ea2bebc6675"
 
 [[package]]
 name = "colorchoice"
@@ -1050,6 +1059,7 @@ dependencies = [
  "bincode",
  "byteorder",
  "clap",
+ "clap_complete",
  "error-chain",
  "futures",
  "grep",
diff --git a/Cargo.toml b/Cargo.toml
index 46e3718..0e6220c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -49,6 +49,7 @@ xdg = "2.5.2"
 xml-rs = "0.8.20"
 xz2 = "0.1.7"
 zstd = { version = "0.12.4", features = [ "zstdmt" ] }
+clap_complete = "4.5.54"
 
 [dependencies.hyper]
 features = ["client", "http1", "http2", "runtime", "stream"]
diff --git a/src/bin/nix-channel-index.rs b/src/bin/nix-channel-index.rs
index 75de785..e847e23 100644
--- a/src/bin/nix-channel-index.rs
+++ b/src/bin/nix-channel-index.rs
@@ -5,7 +5,8 @@ use std::os::unix::ffi::OsStringExt;
 use std::path::PathBuf;
 use std::process;
 
-use clap::Parser;
+use clap::{CommandFactory, Parser};
+use clap_complete::{generate, Shell};
 use error_chain::ChainedError;
 use futures::{future, StreamExt};
 use nix_index::files::FileNode;
@@ -179,12 +180,26 @@ struct Args {
     /// Show a stack trace in the case of a Nix evaluation error
     #[clap(long)]
     show_trace: bool,
+
+    /// Generate shell completions to stdout.
+    #[clap(long)]
+    completions: Option<Shell>,
 }
 
 #[tokio::main]
 async fn main() {
     let args = Args::parse();
 
+    if let Some(shell) = args.completions {
+        generate(
+            shell,
+            &mut Args::command(),
+            "nix-channel-index",
+            &mut io::stdout(),
+        );
+        return;
+    }
+
     if let Err(e) = update_index(&args).await {
         eprintln!("error: {}", e);
 
diff --git a/src/bin/nix-index.rs b/src/bin/nix-index.rs
index 004e0e0..627b14e 100644
--- a/src/bin/nix-index.rs
+++ b/src/bin/nix-index.rs
@@ -5,7 +5,8 @@ use std::io::{self, Write};
 use std::path::PathBuf;
 use std::process;
 
-use clap::Parser;
+use clap::{CommandFactory, Parser};
+use clap_complete::{generate, Shell};
 use error_chain::ChainedError;
 use futures::future::Either;
 use futures::{future, StreamExt};
@@ -153,12 +154,21 @@ struct Args {
     /// Note: does not check if the cached data is up to date! Use only for development.
     #[clap(long)]
     path_cache: bool,
+
+    /// Generate shell completions to stdout.
+    #[clap(long)]
+    completions: Option<Shell>,
 }
 
 #[tokio::main]
 async fn main() {
     let args = Args::parse();
 
+    if let Some(shell) = args.completions {
+        generate(shell, &mut Args::command(), "nix-index", &mut io::stdout());
+        return;
+    }
+
     if let Err(e) = update_index(&args).await {
         eprintln!("error: {}", e);
 
diff --git a/src/bin/nix-locate.rs b/src/bin/nix-locate.rs
index 2c18747..5986041 100644
--- a/src/bin/nix-locate.rs
+++ b/src/bin/nix-locate.rs
@@ -1,13 +1,17 @@
 //! Tool for searching for files in nixpkgs packages
 use std::collections::HashSet;
 use std::ffi::OsStr;
+use std::io;
 use std::path::PathBuf;
 use std::process;
 use std::result;
 use std::str;
 use std::str::FromStr;
 
+use clap::CommandFactory;
 use clap::{value_parser, Parser};
+use clap_complete::generate;
+use clap_complete::Shell;
 use error_chain::error_chain;
 use nix_index::database;
 use nix_index::files::{self, FileTreeEntry, FileType};
@@ -153,7 +157,10 @@ fn locate(args: &Args) -> Result<()> {
 ///
 /// Handles parsing the values of more complex arguments.
 fn process_args(matches: Opts) -> result::Result<Args, clap::Error> {
-    let pattern_arg = matches.pattern;
+    let pattern_arg = matches.pattern.ok_or(Opts::command().error(
+        clap::error::ErrorKind::MissingRequiredArgument,
+        "The argument <PATTERN> is missing",
+    ))?;
     let package_arg = matches.package;
 
     let start_anchor = if matches.at_root { "^" } else { "" };
@@ -237,7 +244,7 @@ fn cache_dir() -> &'static OsStr {
 struct Opts {
     /// Pattern for which to search
     // #[clap(name = "PATTERN")]
-    pattern: String,
+    pattern: Option<String>,
 
     /// Directory where the index is stored
     #[clap(short, long = "db", default_value_os = cache_dir(), env = "NIX_INDEX_DATABASE")]
@@ -293,6 +300,10 @@ struct Opts {
     /// store path are omitted. This is useful for scripts that use the output of nix-locate.
     #[clap(long)]
     minimal: bool,
+
+    /// Generate shell completions to stdout.
+    #[clap(long)]
+    completions: Option<Shell>,
 }
 
 #[derive(clap::ValueEnum, Clone, Copy, Debug)]
@@ -318,6 +329,11 @@ impl FromStr for Color {
 fn main() {
     let args = Opts::parse();
 
+    if let Some(shell) = args.completions {
+        generate(shell, &mut Opts::command(), "nix-locate", &mut io::stdout());
+        return;
+    }
+
     let args = process_args(args).unwrap_or_else(|e| e.exit());
 
     if let Err(e) = locate(&args) {