diff --git a/Cargo.lock b/Cargo.lock
index 53a77ce..70e5536 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -115,46 +115,6 @@ dependencies = [
  "windows-targets",
 ]
 
-[[package]]
-name = "clap"
-version = "4.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "80c21025abd42669a92efc996ef13cfb2c5c627858421ea58d5c3b331a6c134f"
-dependencies = [
- "clap_builder",
- "clap_derive",
-]
-
-[[package]]
-name = "clap_builder"
-version = "4.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "458bf1f341769dfcf849846f65dffdf9146daa56bcd2a47cb4e1de9915567c99"
-dependencies = [
- "anstream",
- "anstyle",
- "clap_lex",
- "strsim",
-]
-
-[[package]]
-name = "clap_derive"
-version = "4.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "307bc0538d5f0f83b8248db3087aa92fe504e4691294d0c96c0eabc33f47ba47"
-dependencies = [
- "heck",
- "proc-macro2",
- "quote",
- "syn",
-]
-
-[[package]]
-name = "clap_lex"
-version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "98cc8fbded0c607b7ba9dd60cd98df59af97e84d24e49c8557331cfc26d301ce"
-
 [[package]]
 name = "colorchoice"
 version = "1.0.0"
@@ -211,12 +171,6 @@ dependencies = [
  "log",
 ]
 
-[[package]]
-name = "heck"
-version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
-
 [[package]]
 name = "hostname"
 version = "0.3.1"
@@ -429,7 +383,6 @@ name = "sonar"
 version = "0.10.0"
 dependencies = [
  "chrono",
- "clap",
  "csv",
  "env_logger",
  "hostname",
@@ -442,12 +395,6 @@ dependencies = [
  "subprocess",
 ]
 
-[[package]]
-name = "strsim"
-version = "0.11.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5ee073c9e4cd00e28217186dbe12796d692868f432bf2e97ee73bed0c56dfa01"
-
 [[package]]
 name = "subprocess"
 version = "0.2.9"
diff --git a/Cargo.toml b/Cargo.toml
index 758d65d..7eb0bbb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,7 +9,6 @@ edition = "2021"
 subprocess = "0.2"
 chrono = "0.4"
 hostname = "0.3"
-clap = { version = "4.5", features = ["derive"] }
 csv = "1.3"
 log = "0.4"
 env_logger = "0.11"
diff --git a/src/main.rs b/src/main.rs
index da2b6d8..1fb36aa 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,7 +1,5 @@
 extern crate env_logger;
 
-use clap::{Parser, Subcommand};
-
 mod amd;
 mod batchless;
 mod command;
@@ -18,60 +16,41 @@ mod util;
 
 const TIMEOUT_SECONDS: u64 = 5; // For subprocesses
 
-#[derive(Parser)]
-#[command(author, version, about, long_about = None)]
-struct Cli {
-    #[command(subcommand)]
-    command: Commands,
-}
-
-#[derive(Subcommand)]
 enum Commands {
     /// Take a snapshot of the currently running processes
     PS {
         /// Synthesize a job ID from the process tree in which a process finds itself
-        #[arg(long, default_value_t = false)]
         batchless: bool,
 
         /// Merge process records that have the same job ID and command name
-        #[arg(long, default_value_t = false)]
         rollup: bool,
 
         /// Include records for jobs that have on average used at least this percentage of CPU,
         /// note this is nonmonotonic [default: none]
-        #[arg(long)]
         min_cpu_percent: Option<f64>,
 
         /// Include records for jobs that presently use at least this percentage of real memory,
         /// note this is nonmonotonic [default: none]
-        #[arg(long)]
         min_mem_percent: Option<f64>,
 
         /// Include records for jobs that have used at least this much CPU time (in seconds)
         /// [default: none]
-        #[arg(long)]
         min_cpu_time: Option<usize>,
 
         /// Exclude records for system jobs (uid < 1000)
-        #[arg(long, default_value_t = false)]
         exclude_system_jobs: bool,
 
         /// Exclude records whose users match these comma-separated names [default: none]
-        #[arg(long)]
         exclude_users: Option<String>,
 
         /// Exclude records whose commands start with these comma-separated names [default: none]
-        #[arg(long)]
         exclude_commands: Option<String>,
 
         /// Create a per-host lockfile in this directory and exit early if the file exists on startup [default: none]
-        #[arg(long)]
         lockdir: Option<String>,
     },
     /// Extract system information
     Sysinfo {},
-    /// Not yet implemented
-    Analyze {},
 }
 
 fn main() {
@@ -83,9 +62,7 @@ fn main() {
 
     env_logger::init();
 
-    let cli = Cli::parse();
-
-    match &cli.command {
+    match &command_line() {
         Commands::PS {
             rollup,
             batchless,
@@ -127,8 +104,151 @@ fn main() {
         Commands::Sysinfo {} => {
             sysinfo::show_system(&timestamp);
         }
-        Commands::Analyze {} => {
-            println!("sonar analyze not yet completed");
+    }
+}
+
+// For the sake of simplicity:
+//  - allow repeated options to overwrite earlier values
+//  - all error reporting is via a generic "usage" message, without specificity as to what was wrong
+
+fn command_line() -> Commands {
+    let mut args = std::env::args();
+    let _executable = args.next();
+    if let Some(command) = args.next() {
+        match command.as_str() {
+            "ps" => {
+                let mut batchless = false;
+                let mut rollup = false;
+                let mut min_cpu_percent = None;
+                let mut min_mem_percent = None;
+                let mut min_cpu_time = None;
+                let mut exclude_system_jobs = false;
+                let mut exclude_users = None;
+                let mut exclude_commands = None;
+                let mut lockdir = None;
+                loop {
+                    if let Some(arg) = args.next() {
+                        match arg.as_str() {
+                            "--batchless" => {
+                                batchless = true;
+                            }
+                            "--rollup" => {
+                                rollup = true;
+                            }
+                            "--exclude-system-jobs" => {
+                                exclude_system_jobs = true;
+                            }
+                            "--exclude-users" => {
+                                (args, exclude_users) = string_value(args);
+                            }
+                            "--exclude-commands" => {
+                                (args, exclude_commands) = string_value(args);
+                            }
+                            "--lockdir" => {
+                                (args, lockdir) = string_value(args);
+                            }
+                            "--min-cpu-percent" => {
+                                (args, min_cpu_percent) = parsed_value::<f64>(args);
+                            }
+                            "--min-mem-percent" => {
+                                (args, min_mem_percent) = parsed_value::<f64>(args);
+                            }
+                            "--min-cpu-time" => {
+                                (args, min_cpu_time) = parsed_value::<usize>(args);
+                            }
+                            _ => {
+                                usage(true);
+                            }
+                        }
+                    } else {
+                        break;
+                    }
+                }
+                return Commands::PS {
+                    batchless,
+                    rollup,
+                    min_cpu_percent,
+                    min_mem_percent,
+                    min_cpu_time,
+                    exclude_system_jobs,
+                    exclude_users,
+                    exclude_commands,
+                    lockdir,
+                }
+            }
+            "sysinfo" => {
+                return Commands::Sysinfo {}
+            }
+            "help" => {
+                usage(false);
+            }
+            _ => {
+                usage(true);
+            }
+        }
+    } else {
+        usage(true);
+    }
+}
+
+fn string_value(mut args: std::env::Args) -> (std::env::Args, Option<String>) {
+    if let Some(val) = args.next() {
+        (args, Some(val))
+    } else {
+        usage(true);
+    }
+}
+
+fn parsed_value<T: std::str::FromStr>(mut args: std::env::Args) -> (std::env::Args, Option<T>) {
+    if let Some(val) = args.next() {
+        match val.parse::<T>() {
+            Ok(value) => {
+                (args, Some(value))
+            }
+            _ => {
+                usage(true);
+            }
         }
+    } else {
+        usage(true);
     }
 }
+
+fn usage(is_error: bool) -> ! {
+    let mut stdout = std::io::stdout();
+    let mut stderr = std::io::stderr();
+    let out: &mut dyn std::io::Write = if is_error { &mut stderr } else { &mut stdout };
+    let _ = out.write(b"Usage: sonar <COMMAND>
+
+Commands:
+  ps       Take a snapshot of the currently running processes
+  sysinfo  Extract system information
+  help     Print this message
+
+Options for `ps`:
+  --batchless
+      Synthesize a job ID from the process tree in which a process finds itself
+  --rollup
+      Merge process records that have the same job ID and command name
+  --min-cpu-percent percentage
+      Include records for jobs that have on average used at least this
+      percentage of CPU, note this is nonmonotonic [default: none]
+  --min-mem-percent percentage
+      Include records for jobs that presently use at least this percentage of
+      real memory, note this is nonmonotonic [default: none]
+  --min-cpu-time seconds
+      Include records for jobs that have used at least this much CPU time
+      [default: none]
+  --exclude-system-jobs
+      Exclude records for system jobs (uid < 1000)
+  --exclude-users user,user,...
+      Exclude records whose users match these names [default: none]
+  --exclude-commands command,command,...
+      Exclude records whose commands start with these names [default: none]
+  --lockdir directory
+      Create a per-host lockfile in this directory and exit early if the file
+      exists on startup [default: none]
+");
+    let _ = out.flush();
+    std::process::exit(if is_error { 2 } else { 0 });
+}