1 files changed, 43 insertions, 0 deletions
diff --git a/src/help.rs b/src/help.rs
new file mode 100644
index 0000000..188f475
--- /dev/null
+++ b/src/help.rs
@@ -0,0 +1,43 @@
+use std::process::ExitCode;
+
+use crate::query;
+use crate::repl;
+use crate::server;
+
+pub const USAGE: &str = "
+Usage: blom [command] [options]
+
+Commands:
+
+ server                   Start the blom server.
+
+ repl                     Start the blom repl.
+ query <query>            Send <query> to the blom server.
+
+ help [<command>]         Print usage.
+
+General options:
+
+ -h, --help               Print usage.
+";
+
+pub fn cmd(args: &[String]) -> ExitCode {
+    if args.is_empty() {
+        println!("{}", USAGE);
+        return ExitCode::from(0);
+    }
+
+    match args[0].as_str() {
+        "server" => println!("{}", server::USAGE),
+        "repl" => println!("{}", repl::USAGE),
+        "query" => println!("{}", query::USAGE),
+        "help" => println!("{}", USAGE),
+        _ => {
+            println!("{}", USAGE);
+            eprintln!("Unknown command {}.", args[0]);
+            return ExitCode::from(1);
+        }
+    }
+
+    ExitCode::SUCCESS
+}