diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3f06267
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,108 @@
+
+# Created by https://www.gitignore.io/api/gradle,jetbrains+all
+# Edit at https://www.gitignore.io/?templates=gradle,jetbrains+all
+
+### JetBrains+all ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### JetBrains+all Patch ###
+# Ignores the whole .idea folder and all .iml files
+# See https://github.com/joeblau/gitignore.io/issues/186 and https://github.com/joeblau/gitignore.io/issues/360
+
+.idea/
+
+# Reason: https://github.com/joeblau/gitignore.io/issues/186#issuecomment-249601023
+
+*.iml
+modules.xml
+.idea/misc.xml
+*.ipr
+
+# Sonarlint plugin
+ .idea/sonarlint
+
+### Gradle ###
+.gradle
+build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache
+
+# # Work around https://youtrack.jetbrains.com/issue/IDEA-116898
+# gradle/wrapper/gradle-wrapper.properties
+
+### Gradle Patch ###
+**/build/
+
+# End of https://www.gitignore.io/api/gradle,jetbrains+all
\ No newline at end of file
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..42e6556
--- /dev/null
+++ b/README.md
@@ -0,0 +1,24 @@
+# CLI
+### Сборка проекта:
+Для сборки проекта используется [gradle](https://docs.gradle.org/current/userguide/installation.html).
+
+Сборка проекта происходит с помощью команды:
+```$bash
+gradle build
+```
+Данная команда создаст ZIP и TAR архивы со всем необходимым для запуска в `build/distributions`.
+
+## Основные компоненты системы:
+- IToken - представление токена команды в системе
+- Parser - модуль обработки строкового представления команды и перевода его в список IToken
+- Context - объект, служащий для хранения текущего состояния системы (текущие переменные, флаг завершения программы)
+- Executor - модуль выполнения команды по списку токенов
+
+## Описание работы
+Команда разбивается на токены с помощью компоненты Parser, каждый токен умеет выводить свое строковое представление. Так, например, токен переменная возвращает значение переменной в качестве значения.
+Затем, полученный список токенов передается в модуль Executor, который исполняет команду,
+на каждом шаге работы запоминая результат работы последней исполненной команды. Результат последнего шага исполнения является результатом исполнения всей команды.
+
+#### Схема выполнения команды:
+![Схема работы](images/schema.png)
+
diff --git a/build.gradle b/build.gradle
new file mode 100644
index 0000000..9056608
--- /dev/null
+++ b/build.gradle
@@ -0,0 +1,17 @@
+group 'ru.ifmo'
+version '1.0-SNAPSHOT'
+
+apply plugin: 'java'
+apply plugin: 'application'
+
+sourceCompatibility = 1.9
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+}
+
+mainClassName = 'ru.ifmo.cli_application.CLI'
\ No newline at end of file
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..01b8bf6
Binary files /dev/null and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..0142f8c
--- /dev/null
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,6 @@
+#Mon Feb 25 07:13:53 MSK 2019
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip
diff --git a/gradlew b/gradlew
new file mode 100755
index 0000000..cccdd3d
--- /dev/null
+++ b/gradlew
@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
new file mode 100644
index 0000000..e95643d
--- /dev/null
+++ b/gradlew.bat
@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/images/schema.png b/images/schema.png
new file mode 100644
index 0000000..1504fb0
Binary files /dev/null and b/images/schema.png differ
diff --git a/settings.gradle b/settings.gradle
new file mode 100644
index 0000000..d02d86e
--- /dev/null
+++ b/settings.gradle
@@ -0,0 +1,3 @@
+rootProject.name = 'cli-application'
+rootProject.name = 'cli-application'
+
diff --git a/src/main/java/ru/ifmo/cli_application/Application.java b/src/main/java/ru/ifmo/cli_application/Application.java
new file mode 100644
index 0000000..34bd817
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/Application.java
@@ -0,0 +1,56 @@
+package ru.ifmo.cli_application;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.List;
+import java.util.Scanner;
+
+import ru.ifmo.cli_application.parser.Parser;
+import ru.ifmo.cli_application.parser.SimpleParser;
+import ru.ifmo.cli_application.tokens.IToken;
+
+/**
+ * Main CLI application class
+ */
+public class Application {
+    private Context ctx;
+    private Parser parser;
+    private Executor executor;
+    private InputStream inputStream;
+    private OutputStream outputStream;
+
+    /**
+     * CLI application constructor
+     * @param inputStream stream for commands input
+     * @param outputStream stream for commands result output
+     */
+    public Application(InputStream inputStream, OutputStream outputStream) {
+        ctx = new Context();
+        parser = new SimpleParser(ctx);
+        this.inputStream = inputStream;
+        this.outputStream = outputStream;
+
+        executor = new Executor(ctx);
+    }
+
+    /**
+     * Method for starting cli application
+     * @throws IOException in case of input or output stream is not working
+     */
+    public void start() throws IOException {
+        Scanner scanner = new Scanner(inputStream);
+
+        while (!ctx.isClosed()) {
+            try {
+                List<IToken> tokens = parser.parseTokens(scanner.nextLine());
+                String result = executor.execute(tokens);
+                outputStream.write(result.getBytes());
+                outputStream.flush();
+            } catch (Throwable e) {
+                outputStream.write(e.getMessage().getBytes());
+                outputStream.flush();
+            }
+        }
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/CLI.java b/src/main/java/ru/ifmo/cli_application/CLI.java
new file mode 100644
index 0000000..cfea95d
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/CLI.java
@@ -0,0 +1,10 @@
+package ru.ifmo.cli_application;
+
+import java.io.IOException;
+
+public class CLI {
+    public static void main(String[] args) throws IOException {
+        Application application = new Application(System.in, System.out);
+        application.start();
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/Context.java b/src/main/java/ru/ifmo/cli_application/Context.java
new file mode 100644
index 0000000..ebb9ef5
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/Context.java
@@ -0,0 +1,25 @@
+package ru.ifmo.cli_application;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class Context {
+    private Map<String, String> variables = new HashMap<>();
+    private boolean isClosed = false;
+
+    public void setVariable(String variable, String result) {
+        this.variables.put(variable, result);
+    }
+
+    public String getVariable(String variable) {
+        return this.variables.getOrDefault(variable, "");
+    }
+
+    public void exit() {
+        isClosed = true;
+    }
+
+    public boolean isClosed() {
+        return isClosed;
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/Executor.java b/src/main/java/ru/ifmo/cli_application/Executor.java
new file mode 100644
index 0000000..09cdbc7
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/Executor.java
@@ -0,0 +1,43 @@
+package ru.ifmo.cli_application;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import ru.ifmo.cli_application.tokens.IDelimiter;
+import ru.ifmo.cli_application.tokens.IExecutable;
+import ru.ifmo.cli_application.tokens.IToken;
+
+public class Executor {
+    private Context ctx;
+
+    public Executor(Context ctx) {
+        this.ctx = ctx;
+    }
+
+    public String execute(List<IToken> tokens) {
+        String prevOutput = "";
+        if (tokens.isEmpty()) {
+            return "";
+        }
+        List<IToken> tokensToExecute = new ArrayList<>();
+        IExecutable executableCommand = null;
+        for (IToken token : tokens) {
+            if (executableCommand == null) {
+                executableCommand = ((IExecutable) token);
+                continue;
+            }
+            if (token instanceof IDelimiter) {
+                prevOutput = executableCommand.execute(tokensToExecute, prevOutput);
+                executableCommand = null;
+                tokensToExecute.clear();
+                continue;
+            }
+            tokensToExecute.add(token);
+        }
+        if (executableCommand != null) {
+            prevOutput = executableCommand.execute(tokensToExecute, prevOutput);
+        }
+        prevOutput += "\n";
+        return prevOutput;
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/commands/CatCommand.java b/src/main/java/ru/ifmo/cli_application/commands/CatCommand.java
new file mode 100644
index 0000000..d1186ee
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/commands/CatCommand.java
@@ -0,0 +1,36 @@
+package ru.ifmo.cli_application.commands;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.List;
+import java.util.stream.Stream;
+
+import ru.ifmo.cli_application.tokens.IExecutable;
+import ru.ifmo.cli_application.tokens.IToken;
+
+/**
+ * Class for concatenation files command
+ */
+public class CatCommand implements IToken, IExecutable {
+    @Override
+    public String execute(List<IToken> args, String inputStream) {
+        if (args.size() == 0) {
+            return inputStream;
+        }
+        StringBuilder resultString = new StringBuilder();
+        for (IToken fileName : args) {
+            try (Stream<String> lines = Files.lines(Paths.get(fileName.getValue()))) {
+                lines.forEach((s)->resultString.append(s).append('\n'));
+            } catch (IOException e) {
+                return "File not found: " + fileName.getValue();
+            }
+        }
+        return resultString.toString();
+    }
+
+    @Override
+    public String getValue() {
+        return "cat";
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/commands/Command.java b/src/main/java/ru/ifmo/cli_application/commands/Command.java
new file mode 100644
index 0000000..e606f3f
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/commands/Command.java
@@ -0,0 +1,42 @@
+package ru.ifmo.cli_application.commands;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+
+import ru.ifmo.cli_application.tokens.IExecutable;
+import ru.ifmo.cli_application.tokens.IToken;
+
+/**
+ * Class for execution external bash commands
+ */
+public class Command implements IToken, IExecutable {
+    private String commandName;
+
+    public Command(String commandName) {
+        this.commandName = commandName;
+    }
+
+    @Override
+    public String execute(List<IToken> args, String inputStream) {
+        try {
+            List<String> result = new ArrayList<>();
+            result.add(commandName);
+            for (IToken arg : args) {
+                result.add(arg.getValue());
+            }
+            ProcessBuilder processBuilder = new ProcessBuilder();
+            processBuilder.command(result);
+            Process process = processBuilder.start();
+            InputStream processOutput = process.getInputStream();
+            return new String(processOutput.readAllBytes());
+        } catch (IOException e) {
+            return commandName + ": command not found";
+        }
+    }
+
+    public String getValue() {
+        return commandName;
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/commands/EchoCommand.java b/src/main/java/ru/ifmo/cli_application/commands/EchoCommand.java
new file mode 100644
index 0000000..741f8cc
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/commands/EchoCommand.java
@@ -0,0 +1,26 @@
+package ru.ifmo.cli_application.commands;
+
+import java.util.List;
+
+import ru.ifmo.cli_application.tokens.IExecutable;
+import ru.ifmo.cli_application.tokens.IToken;
+
+/**
+ * Class for echo command
+ */
+public class EchoCommand implements IToken, IExecutable {
+    @Override
+    public String execute(List<IToken> args, String inputStream) {
+        StringBuilder stringBuilder = new StringBuilder();
+        for (IToken arg : args) {
+            stringBuilder.append(arg.getValue());
+            stringBuilder.append(' ');
+        }
+        return stringBuilder.toString();
+    }
+
+    @Override
+    public String getValue() {
+        return "echo";
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/commands/ExitCommand.java b/src/main/java/ru/ifmo/cli_application/commands/ExitCommand.java
new file mode 100644
index 0000000..62d4295
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/commands/ExitCommand.java
@@ -0,0 +1,29 @@
+package ru.ifmo.cli_application.commands;
+
+import java.util.List;
+
+import ru.ifmo.cli_application.Context;
+import ru.ifmo.cli_application.tokens.IExecutable;
+import ru.ifmo.cli_application.tokens.IToken;
+
+/**
+ * Class for exit CLI application command
+ */
+public class ExitCommand implements IToken, IExecutable {
+    private Context ctx;
+
+    public ExitCommand(Context ctx) {
+        this.ctx = ctx;
+    }
+
+    @Override
+    public String execute(List<IToken> args, String inputStream) {
+        ctx.exit();
+        return "";
+    }
+
+    @Override
+    public String getValue() {
+        return "exit";
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/commands/PwdCommand.java b/src/main/java/ru/ifmo/cli_application/commands/PwdCommand.java
new file mode 100644
index 0000000..2fc4bf1
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/commands/PwdCommand.java
@@ -0,0 +1,21 @@
+package ru.ifmo.cli_application.commands;
+
+import java.util.List;
+
+import ru.ifmo.cli_application.tokens.IExecutable;
+import ru.ifmo.cli_application.tokens.IToken;
+
+/**
+ * Class for showing current working directory command
+ */
+public class PwdCommand implements IToken, IExecutable {
+    @Override
+    public String execute(List<IToken> args, String inputStream) {
+        return System.getProperty("user.dir");
+    }
+
+    @Override
+    public String getValue() {
+        return "pwd";
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/commands/WcCommand.java b/src/main/java/ru/ifmo/cli_application/commands/WcCommand.java
new file mode 100644
index 0000000..2ff4a56
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/commands/WcCommand.java
@@ -0,0 +1,82 @@
+package ru.ifmo.cli_application.commands;
+
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+import ru.ifmo.cli_application.tokens.IExecutable;
+import ru.ifmo.cli_application.tokens.IToken;
+
+/**
+ * Class for calculation of lines, words and bytes count for each file
+ */
+public class WcCommand implements IToken, IExecutable {
+    @Override
+    public String execute(List<IToken> args, String inputStream) {
+        if (args.size() == 0) {
+            Stats inputStreamStats = new Stats(null, inputStream);
+            return inputStreamStats.statisticWithoutFileName();
+        }
+        List<Stats> stats = new ArrayList<>();
+        for (IToken arg : args) {
+            try (Scanner scanner = new Scanner(new FileInputStream(arg.getValue()))) {
+                StringBuilder fileContent = new StringBuilder();
+                while (scanner.hasNextLine()) {
+                    fileContent.append(scanner.nextLine());
+                    fileContent.append('\n');
+                }
+                stats.add(new Stats(arg.getValue(), fileContent.toString()));
+            } catch (FileNotFoundException e) {
+                return "File not found: " + arg.getValue();
+            }
+        }
+        if (stats.size() == 1) {
+            return stats.get(0).statisticWithFileName();
+        }
+        stats.add(new Stats(stats));
+        StringBuilder stringBuilder = new StringBuilder();
+        for (Stats stat : stats) {
+            stringBuilder.append(stat.statisticWithFileName());
+            stringBuilder.append('\n');
+        }
+        return stringBuilder.toString();
+    }
+
+    @Override
+    public String getValue() {
+        return "wc";
+    }
+
+    private class Stats {
+        private long linesCount;
+        private long wordsCount;
+        private long bytesCount;
+        private String fileName;
+
+        Stats(List<Stats> stats) {
+            fileName = "total";
+            for (Stats stat : stats) {
+                this.linesCount += stat.linesCount;
+                this.wordsCount += stat.wordsCount;
+                this.bytesCount += stat.bytesCount;
+            }
+        }
+
+        Stats(String fileName, String string) {
+            linesCount = string.chars().filter(ch -> ch == '\n').count() + 1;
+            wordsCount = string.split("[ \n\t\r]+").length;
+            bytesCount = string.getBytes().length;
+            this.fileName = fileName;
+        }
+
+        public String statisticWithoutFileName() {
+            return String.format("%d\t%d\t%d", linesCount, wordsCount, bytesCount);
+        }
+
+        public String statisticWithFileName() {
+            return String.format("%d\t%d\t%d\t%s", linesCount, wordsCount, bytesCount, fileName);
+        }
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/parser/Parser.java b/src/main/java/ru/ifmo/cli_application/parser/Parser.java
new file mode 100644
index 0000000..752e88f
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/parser/Parser.java
@@ -0,0 +1,54 @@
+package ru.ifmo.cli_application.parser;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import ru.ifmo.cli_application.tokens.IToken;
+
+/**
+ *  Parses string to {@link List<IToken>} using {@link ParserRule}
+ */
+public abstract class Parser {
+    private List<ParserRule> rules;
+
+    public Parser() {
+        this.rules = new ArrayList<>();
+    }
+
+    /**
+     * Method to add new parsing rule
+     * @param parserRule
+     */
+    public void addParsingRule(ParserRule parserRule) {
+        this.rules.add(parserRule);
+    }
+
+    /**
+     * Function that split command string to list of string tokens and then, parse each token using {@link ParserRule}
+     * @param command
+     * @return List of parsed tokens
+     */
+    public List<IToken> parseTokens(String command) {
+        List<String> splitedCommand = commandPreprocessing(command);
+        List<IToken> outputTokens = new ArrayList<>(splitedCommand.size());
+        for (String commandToken : splitedCommand) {
+            if (commandToken.isEmpty()) {
+                continue;
+            }
+            for (ParserRule rule : rules) {
+                if (rule.getPredicate().apply(commandToken, outputTokens)) {
+                    outputTokens.add(rule.getConstructor().apply(commandToken));
+                    break;
+                }
+            }
+        }
+        return outputTokens;
+    }
+
+    /**
+     * Function for split and preprocess command
+     * @param command
+     * @return {@link List<String>} of preprocessed command
+     */
+    public abstract List<String> commandPreprocessing(String command);
+}
diff --git a/src/main/java/ru/ifmo/cli_application/parser/ParserRule.java b/src/main/java/ru/ifmo/cli_application/parser/ParserRule.java
new file mode 100644
index 0000000..32d7fb7
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/parser/ParserRule.java
@@ -0,0 +1,28 @@
+package ru.ifmo.cli_application.parser;
+
+import java.util.List;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+import ru.ifmo.cli_application.tokens.IToken;
+
+/**
+ * Rule for parsing string tokens to IToken
+ */
+public class ParserRule {
+    private BiFunction<String, List<IToken>, Boolean> predicate;
+    private Function<String, IToken> constructor;
+
+    public ParserRule(BiFunction<String, List<IToken>, Boolean> predicate, Function<String, IToken> constructor) {
+        this.predicate = predicate;
+        this.constructor = constructor;
+    }
+
+    public BiFunction<String, List<IToken>, Boolean> getPredicate() {
+        return predicate;
+    }
+
+    public Function<String, IToken> getConstructor() {
+        return constructor;
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/parser/SimpleParser.java b/src/main/java/ru/ifmo/cli_application/parser/SimpleParser.java
new file mode 100644
index 0000000..6faee67
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/parser/SimpleParser.java
@@ -0,0 +1,70 @@
+package ru.ifmo.cli_application.parser;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Function;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+import ru.ifmo.cli_application.Context;
+import ru.ifmo.cli_application.commands.*;
+import ru.ifmo.cli_application.tokens.*;
+
+/**
+ * Parser implementation for our CLI application
+ */
+public class SimpleParser extends Parser {
+    private static Pattern splittingPattern = Pattern.compile("[^\\s\"']+|\"[^\"]*\"|'[^']*'");
+    private Context ctx;
+
+    public SimpleParser(Context ctx) {
+        this.ctx = ctx;
+        addParsingRules();
+    }
+
+    private void addParsingRules() {
+        List<ParserRule> predicates = new ArrayList<>();
+        Function<List<IToken>, Boolean> isCommand = (List<IToken> t) -> t.size() == 0 || t.get(t.size() - 1) instanceof IDelimiter;
+        predicates.add(new ParserRule((String s, List<IToken> t) -> s.startsWith("\'") && s.endsWith("\'"), FullyQuoted::new));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> s.startsWith("\"") && s.endsWith("\""), (String s) -> new Quoted(this, s)));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> s.startsWith("$"), (String s) -> new Variable(s, ctx)));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> s.equals("|"), (String s) -> new Pipe()));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> s.contains("="), (String s) -> new AssigningOperator(s, ctx)));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> isCommand.apply(t) && s.equals("cat"), (String s) -> new CatCommand()));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> isCommand.apply(t) && s.equals("echo"), (String s) -> new EchoCommand()));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> isCommand.apply(t) && s.equals("pwd"), (String s) -> new PwdCommand()));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> isCommand.apply(t) && s.equals("wc"), (String s) -> new WcCommand()));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> isCommand.apply(t) && s.equals("exit"), (String s) -> new ExitCommand(ctx)));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> isCommand.apply(t), Command::new));
+        predicates.add(new ParserRule((String s, List<IToken> t) -> true, Argument::new));
+        for (ParserRule p : predicates) {
+            super.addParsingRule(p);
+        }
+    }
+
+    public List<String> commandPreprocessing(String command) {
+        Matcher matcher = splittingPattern.matcher(command);
+        List<String> list = new ArrayList<>();
+        while (matcher.find()) {
+            list.add(matcher.group());
+        }
+        List<String> finalList = new ArrayList<>();
+        for (String elem : list) {
+            if (elem.contains("$") && !elem.startsWith("\'") && !elem.endsWith("\'")) {
+                String[] splitedElem = elem.split("\\$");
+                if (elem.startsWith("$")) {
+                    splitedElem[0] = new Variable("$" + splitedElem[0], ctx).getValue();
+                }
+                for (int i = 1; i < splitedElem.length; i++) {
+                    splitedElem[i] = new Variable("$" + splitedElem[i], ctx).getValue();
+                }
+                finalList.add(Arrays.stream(splitedElem).collect(Collectors.joining("")));
+            } else {
+                finalList.add(elem);
+            }
+        }
+        return finalList;
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/tokens/Argument.java b/src/main/java/ru/ifmo/cli_application/tokens/Argument.java
new file mode 100644
index 0000000..8856b01
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/tokens/Argument.java
@@ -0,0 +1,17 @@
+package ru.ifmo.cli_application.tokens;
+
+/**
+ * Command`s argument
+ */
+public class Argument implements IToken {
+    private String value;
+
+    public Argument(String value) {
+        this.value = value;
+    }
+
+    @Override
+    public String getValue() {
+        return this.value;
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/tokens/AssigningOperator.java b/src/main/java/ru/ifmo/cli_application/tokens/AssigningOperator.java
new file mode 100644
index 0000000..aec6114
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/tokens/AssigningOperator.java
@@ -0,0 +1,37 @@
+package ru.ifmo.cli_application.tokens;
+
+import java.util.List;
+
+import ru.ifmo.cli_application.Context;
+
+/**
+ * Class for assigning operator execution
+ */
+public class AssigningOperator implements IToken, IExecutable {
+    private String rawString;
+    private Context ctx;
+
+    public AssigningOperator(String s, Context ctx) {
+        this.rawString = s;
+        if (!this.rawString.contains("=")) {
+            throw new IllegalArgumentException("first argument should contains '='");
+        }
+        if (ctx == null) {
+            throw new NullPointerException("context should be initialized");
+        }
+        this.ctx = ctx;
+    }
+
+
+    @Override
+    public String execute(List<IToken> args, String inputStream) {
+        String[] splitedString = rawString.split("=");
+        ctx.setVariable(splitedString[0], splitedString[1]);
+        return "";
+    }
+
+    @Override
+    public String getValue() {
+        return "=";
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/tokens/FullyQuoted.java b/src/main/java/ru/ifmo/cli_application/tokens/FullyQuoted.java
new file mode 100644
index 0000000..30dae6d
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/tokens/FullyQuoted.java
@@ -0,0 +1,16 @@
+package ru.ifmo.cli_application.tokens;
+
+/**
+ * Class for fully quoted token
+ */
+public class FullyQuoted implements IToken {
+    private String string;
+
+    public FullyQuoted(String string) {
+        this.string = string.substring(1, string.length() - 1);
+    }
+
+    public String getValue() {
+        return string;
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/tokens/IDelimiter.java b/src/main/java/ru/ifmo/cli_application/tokens/IDelimiter.java
new file mode 100644
index 0000000..8e2d5e4
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/tokens/IDelimiter.java
@@ -0,0 +1,7 @@
+package ru.ifmo.cli_application.tokens;
+
+/**
+ * Flag interface for delimiter tokens
+ */
+public interface IDelimiter {
+}
diff --git a/src/main/java/ru/ifmo/cli_application/tokens/IExecutable.java b/src/main/java/ru/ifmo/cli_application/tokens/IExecutable.java
new file mode 100644
index 0000000..e9afac9
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/tokens/IExecutable.java
@@ -0,0 +1,17 @@
+package ru.ifmo.cli_application.tokens;
+
+import java.util.List;
+
+/**
+ * Interface of executable commands
+ */
+public interface IExecutable {
+    /**
+     * Function to execute command
+     *
+     * @param args        command arguments
+     * @param inputStream result of previous commands execution in pipe
+     * @return result of command execution
+     */
+    String execute(List<IToken> args, String inputStream);
+}
diff --git a/src/main/java/ru/ifmo/cli_application/tokens/IToken.java b/src/main/java/ru/ifmo/cli_application/tokens/IToken.java
new file mode 100644
index 0000000..8c82f22
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/tokens/IToken.java
@@ -0,0 +1,12 @@
+package ru.ifmo.cli_application.tokens;
+
+/**
+ *  Interface for all command tokens
+ */
+public interface IToken {
+    /**
+     * Getter for string interpretation of token
+     * @return
+     */
+    String getValue();
+}
diff --git a/src/main/java/ru/ifmo/cli_application/tokens/Pipe.java b/src/main/java/ru/ifmo/cli_application/tokens/Pipe.java
new file mode 100644
index 0000000..c550f9b
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/tokens/Pipe.java
@@ -0,0 +1,8 @@
+package ru.ifmo.cli_application.tokens;
+
+public class Pipe implements IToken, IDelimiter {
+    @Override
+    public String getValue() {
+        return "|";
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/tokens/Quoted.java b/src/main/java/ru/ifmo/cli_application/tokens/Quoted.java
new file mode 100644
index 0000000..bc272c1
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/tokens/Quoted.java
@@ -0,0 +1,26 @@
+package ru.ifmo.cli_application.tokens;
+
+import java.util.List;
+
+import ru.ifmo.cli_application.parser.Parser;
+
+public class Quoted implements IToken {
+    private String string;
+    private Parser parser;
+
+    public Quoted(Parser parser, String string) {
+        this.parser = parser;
+        this.string = string.substring(1, string.length() - 1);
+    }
+
+    @Override
+    public String getValue() {
+        List<IToken> tokens = parser.parseTokens(this.string);
+        StringBuilder result = new StringBuilder();
+        for (IToken token : tokens) {
+            result.append(token.getValue());
+            result.append(" ");
+        }
+        return result.toString();
+    }
+}
diff --git a/src/main/java/ru/ifmo/cli_application/tokens/Variable.java b/src/main/java/ru/ifmo/cli_application/tokens/Variable.java
new file mode 100644
index 0000000..9f69e83
--- /dev/null
+++ b/src/main/java/ru/ifmo/cli_application/tokens/Variable.java
@@ -0,0 +1,17 @@
+package ru.ifmo.cli_application.tokens;
+
+import ru.ifmo.cli_application.Context;
+
+public class Variable implements IToken {
+    String variable;
+    Context ctx;
+
+    public Variable(String var, Context ctx) {
+        this.variable = var;
+        this.ctx = ctx;
+    }
+
+    public String getValue() {
+        return ctx.getVariable(variable.substring(1));
+    }
+}
diff --git a/src/test/java/ru/ifmo/cli_application/commands/EchoCommandTest.java b/src/test/java/ru/ifmo/cli_application/commands/EchoCommandTest.java
new file mode 100644
index 0000000..a812638
--- /dev/null
+++ b/src/test/java/ru/ifmo/cli_application/commands/EchoCommandTest.java
@@ -0,0 +1,20 @@
+package ru.ifmo.cli_application.commands;
+
+import org.junit.Test;
+import ru.ifmo.cli_application.tokens.FullyQuoted;
+import ru.ifmo.cli_application.tokens.IToken;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+
+public class EchoCommandTest {
+    @Test
+    public void testEcho() {
+        EchoCommand echoCommand = new EchoCommand();
+        List<IToken> arguments = Arrays.asList(new FullyQuoted[]{new FullyQuoted("\"hello\"")});
+        String result = echoCommand.execute(arguments, "");
+        assertEquals("hello ", result);
+    }
+}
diff --git a/src/test/java/ru/ifmo/cli_application/commands/ExitCommandTest.java b/src/test/java/ru/ifmo/cli_application/commands/ExitCommandTest.java
new file mode 100644
index 0000000..3d0def6
--- /dev/null
+++ b/src/test/java/ru/ifmo/cli_application/commands/ExitCommandTest.java
@@ -0,0 +1,16 @@
+package ru.ifmo.cli_application.commands;
+
+import org.junit.Test;
+import ru.ifmo.cli_application.Context;
+
+import static org.junit.Assert.assertTrue;
+
+public class ExitCommandTest {
+    @Test
+    public void testExit() {
+        Context ctx = new Context();
+        ExitCommand exitCommand = new ExitCommand(ctx);
+        exitCommand.execute(null, null);
+        assertTrue(ctx.isClosed());
+    }
+}
diff --git a/src/test/java/ru/ifmo/cli_application/commands/WcCommandTest.java b/src/test/java/ru/ifmo/cli_application/commands/WcCommandTest.java
new file mode 100644
index 0000000..86a8be3
--- /dev/null
+++ b/src/test/java/ru/ifmo/cli_application/commands/WcCommandTest.java
@@ -0,0 +1,16 @@
+package ru.ifmo.cli_application.commands;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+
+import static org.junit.Assert.assertEquals;
+
+public class WcCommandTest {
+    @Test
+    public void testWcWithoutArgs() {
+        WcCommand command = new WcCommand();
+        String result = command.execute(new ArrayList<>(), "one two three");
+        assertEquals("1\t3\t13", result);
+    }
+}
diff --git a/src/test/java/ru/ifmo/cli_application/full_tests/FullTest.java b/src/test/java/ru/ifmo/cli_application/full_tests/FullTest.java
new file mode 100644
index 0000000..f35e91f
--- /dev/null
+++ b/src/test/java/ru/ifmo/cli_application/full_tests/FullTest.java
@@ -0,0 +1,42 @@
+package ru.ifmo.cli_application.full_tests;
+
+import java.io.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.stream.Collector;
+import java.util.stream.Collectors;
+
+import org.junit.Test;
+import ru.ifmo.cli_application.Application;
+
+import static org.junit.Assert.assertEquals;
+
+public class FullTest {
+    private String executeCommand(List<String> command) throws IOException {
+        List<String> commands = new ArrayList<>(command);
+        commands.add("exit");
+        InputStream inputStream = new ByteArrayInputStream(commands.stream().collect(Collectors.joining("\n")).getBytes());
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        Application app = new Application(inputStream, outputStream);
+        app.start();
+        return new String(outputStream.toByteArray());
+    }
+
+    @Test
+    public void echoVariableTest() throws IOException {
+        assertEquals("\n12 \n\n", executeCommand(Arrays.asList("x=12", "echo $x")));
+    }
+
+    @Test
+    public void echoVariableConcatTest() throws IOException {
+        assertEquals("\n1212 \n\n", executeCommand(Arrays.asList("x=12", "echo 12$x")));
+    }
+
+    @Test
+    public void echoFromCommand() throws IOException {
+        assertEquals("\n\n12 \n\n", executeCommand(Arrays.asList("x=ec", "y=ho", "$x$y 12")));
+    }
+
+}
diff --git a/src/test/java/ru/ifmo/cli_application/parser/SimpleParserTest.java b/src/test/java/ru/ifmo/cli_application/parser/SimpleParserTest.java
new file mode 100644
index 0000000..d063a4a
--- /dev/null
+++ b/src/test/java/ru/ifmo/cli_application/parser/SimpleParserTest.java
@@ -0,0 +1,86 @@
+package ru.ifmo.cli_application.parser;
+
+import org.junit.Test;
+import ru.ifmo.cli_application.Context;
+import ru.ifmo.cli_application.commands.CatCommand;
+import ru.ifmo.cli_application.commands.EchoCommand;
+import ru.ifmo.cli_application.tokens.*;
+
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class SimpleParserTest {
+    @Test
+    public void testParsingOneInnerCommand() {
+        Context ctx = new Context();
+        Parser parser = new SimpleParser(ctx);
+        List<IToken> tokens = parser.parseTokens("echo");
+        assertEquals(1, tokens.size());
+        assertTrue(tokens.get(0) instanceof EchoCommand);
+    }
+
+    @Test
+    public void testParsingInnerCommandWithArgs() {
+        Context ctx = new Context();
+        Parser parser = new SimpleParser(ctx);
+        List<IToken> tokens = parser.parseTokens("echo 123");
+        assertEquals(2, tokens.size());
+        assertTrue(tokens.get(0) instanceof EchoCommand);
+        assertTrue(tokens.get(1) instanceof Argument);
+    }
+
+    @Test
+    public void testParsingCommandsWithPipe() {
+        Context ctx = new Context();
+        Parser parser = new SimpleParser(ctx);
+        List<IToken> tokens = parser.parseTokens("echo 123 | cat");
+        assertEquals(4, tokens.size());
+        assertTrue(tokens.get(0) instanceof EchoCommand);
+        assertTrue(tokens.get(1) instanceof Argument);
+        assertTrue(tokens.get(2) instanceof Pipe);
+        assertTrue(tokens.get(3) instanceof CatCommand);
+    }
+
+
+    @Test
+    public void testParsingCommandWithQuotedArg() {
+        Context ctx = new Context();
+        Parser parser = new SimpleParser(ctx);
+        List<IToken> tokens = parser.parseTokens("echo \"123 | cat\"");
+        assertEquals(2, tokens.size());
+        assertTrue(tokens.get(0) instanceof EchoCommand);
+        assertTrue(tokens.get(1) instanceof Quoted);
+    }
+
+    @Test
+    public void testParsingCommandWithFullyQuotedArg() {
+        Context ctx = new Context();
+        Parser parser = new SimpleParser(ctx);
+        List<IToken> tokens = parser.parseTokens("echo \'123 | cat\'");
+        assertEquals(2, tokens.size());
+        assertTrue(tokens.get(0) instanceof EchoCommand);
+        assertTrue(tokens.get(1) instanceof FullyQuoted);
+    }
+
+    @Test
+    public void testParsingCommandWithFullyQuotedArgContainsQuote() {
+        Context ctx = new Context();
+        Parser parser = new SimpleParser(ctx);
+        List<IToken> tokens = parser.parseTokens("echo \'1\" | 2\'");
+        assertEquals(2, tokens.size());
+        assertTrue(tokens.get(0) instanceof EchoCommand);
+        assertTrue(tokens.get(1) instanceof FullyQuoted);
+    }
+
+    @Test
+    public void testParsingCommandWithFullyQuotedArgWithDollar() {
+        Context ctx = new Context();
+        Parser parser = new SimpleParser(ctx);
+        List<IToken> tokens = parser.parseTokens("echo \'$x\'");
+        assertEquals(2, tokens.size());
+        assertTrue(tokens.get(0) instanceof EchoCommand);
+        assertTrue(tokens.get(1) instanceof FullyQuoted);
+    }
+}
diff --git a/src/test/java/ru/ifmo/cli_application/tokens/AssigningOperatorTest.java b/src/test/java/ru/ifmo/cli_application/tokens/AssigningOperatorTest.java
new file mode 100644
index 0000000..836d16d
--- /dev/null
+++ b/src/test/java/ru/ifmo/cli_application/tokens/AssigningOperatorTest.java
@@ -0,0 +1,23 @@
+package ru.ifmo.cli_application.tokens;
+
+import org.junit.Test;
+import ru.ifmo.cli_application.Context;
+
+import static org.junit.Assert.assertEquals;
+
+public class AssigningOperatorTest {
+    @Test
+    public void testAssigning() {
+        Context context = new Context();
+
+        AssigningOperator operator = new AssigningOperator("h=5", context);
+        operator.execute(null, null);
+        assertEquals("5", context.getVariable("h"));
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testAssigningWithStringWithoutEquals() {
+        Context context = new Context();
+        AssigningOperator operator = new AssigningOperator("h5", context);
+    }
+}