diff --git a/Cargo.lock b/Cargo.lock
index 113216c..e585234 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -259,6 +259,7 @@ version = "0.1.0"
 dependencies = [
  "dirs",
  "mlua",
+ "peg",
  "rustyline",
  "tracing",
  "tracing-appender",
@@ -303,6 +304,33 @@ version = "1.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "692fcb63b64b1758029e0a96ee63e049ce8c5948587f2f7208df04625e5f6b56"
 
+[[package]]
+name = "peg"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "07c0b841ea54f523f7aa556956fbd293bcbe06f2e67d2eb732b7278aaf1d166a"
+dependencies = [
+ "peg-macros",
+ "peg-runtime",
+]
+
+[[package]]
+name = "peg-macros"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5aa52829b8decbef693af90202711348ab001456803ba2a98eb4ec8fb70844c"
+dependencies = [
+ "peg-runtime",
+ "proc-macro2",
+ "quote",
+]
+
+[[package]]
+name = "peg-runtime"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c719dcf55f09a3a7e764c6649ab594c18a177e3599c467983cdf644bfc0a4088"
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.7"
diff --git a/Cargo.toml b/Cargo.toml
index f6e91a5..1719df6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,6 +16,7 @@ whoami = "1.2.0"                  # Utils for fetching user data
 rustyline = "9.0.0"               # Read user input
 tracing = "0.1.29"                #
 tracing-appender = "0.2.0"        # Logging
+peg = "0.7.0"                     # Parsing
 
 [dependencies.mlua]               # Lua interpreter
 version = "0.6.6"                 #
diff --git a/src/lib.rs b/src/lib.rs
index c23c1d3..e32050a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,2 +1,3 @@
 pub mod core;
 pub mod log; // TODO: rename this module
+pub mod parser;
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
new file mode 100644
index 0000000..360cc6b
--- /dev/null
+++ b/src/parser/mod.rs
@@ -0,0 +1,3 @@
+//! NeoSH command parser
+
+pub mod structure;
diff --git a/src/parser/structure.rs b/src/parser/structure.rs
new file mode 100644
index 0000000..b962c57
--- /dev/null
+++ b/src/parser/structure.rs
@@ -0,0 +1,52 @@
+/// Command is what user sends. Consists of [CommandUnit]
+pub struct Command(Vec<CommandUnit>);
+
+// TODO: Operator as an enum
+/// Part of a [Command]. Can be either an [Instruction] or an Operator
+pub enum CommandUnit {
+    Instruction(Instruction),
+    Operator(String),
+}
+
+/// Instruction is a something that is called with [InstructionUnit]
+pub struct Instruction {
+    callable: String,
+    children: Vec<InstructionUnit>,
+}
+
+/// Either an argument or a [Flag]
+pub enum InstructionUnit {
+    Arg(String),
+    Flag(Flag),
+}
+
+/// Flag parameters
+///
+/// name - what comes after `--` or `-`
+/// value - what we pass to the flag
+/// length - see [FlagLength]
+/// storage - see [FlagStorage]
+pub struct Flag {
+    name: String,
+    value: Option<String>,
+    length: FlagLength,
+    storage: FlagStorage,
+}
+
+/// Flag length type
+///
+/// Short - `-`
+/// Long - `--`
+pub enum FlagLength {
+    Short,
+    Long,
+}
+
+/// How flag storages it's value
+// Inner - --a=b
+// Outer - --a b
+pub enum FlagStorage {
+    Inner,
+    Outer,
+}
+