diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..496b3f0
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,17 @@
+language: kotlin
+
+jdk:
+  - oraclejdk9
+
+os:
+  - linux
+
+before_script:
+  - wget https://services.gradle.org/distributions/gradle-4.5.1-bin.zip
+  - unzip gradle-4.5.1-bin.zip
+  - export GRADLE_HOME=$PWD/gradle-4.5.1
+  - export PATH=$GRADLE_HOME/bin:$PATH
+
+script: 
+  - chmod +x build.sh
+  - bash build.sh
\ No newline at end of file
diff --git a/bash/README.md b/bash/README.md
new file mode 100644
index 0000000..ba1db53
--- /dev/null
+++ b/bash/README.md
@@ -0,0 +1,10 @@
+# Архитектура
+![Image](https://pp.userapi.com/c845321/v845321454/1962dd/W9ATvrz_K6k.jpg)
+
+На картинке показана упрощённая модель потока данных в архитектуре
+
+Сначала строка из stdin попадает в лексер, где разбивается на токены
+
+Оттуда токены передаются в парсер вместе с окружением, где по пайпам токены делятся на команды: первый токен - имя, остальные - аргументы
+
+Дальше этот массив передаётся контроллеру, который исполняет команды, передавая выходной поток одной команды на вход другой
diff --git a/bash/build.gradle b/bash/build.gradle
new file mode 100644
index 0000000..60bedc5
--- /dev/null
+++ b/bash/build.gradle
@@ -0,0 +1,33 @@
+plugins {
+    id 'org.jetbrains.kotlin.jvm' version '1.2.51'
+}
+
+version '1.0-SNAPSHOT'
+
+apply plugin: 'kotlin'
+apply plugin: 'application'
+
+mainClassName = 'hse.nedikov.bash.Main'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // https://mvnrepository.com/artifact/junit/junit
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+
+}
+
+jar {
+    manifest { attributes 'Main-Class': "${mainClassName}" }
+    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
+}
+
+compileKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
+compileTestKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
\ No newline at end of file
diff --git a/bash/gradle/wrapper/gradle-wrapper.jar b/bash/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..1948b90
Binary files /dev/null and b/bash/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/bash/gradle/wrapper/gradle-wrapper.properties b/bash/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..d2c45a4
--- /dev/null
+++ b/bash/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.8-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/bash/gradlew b/bash/gradlew
new file mode 100644
index 0000000..cccdd3d
--- /dev/null
+++ b/bash/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/bash/gradlew.bat b/bash/gradlew.bat
new file mode 100644
index 0000000..f955316
--- /dev/null
+++ b/bash/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/bash/settings.gradle b/bash/settings.gradle
new file mode 100644
index 0000000..2c164f0
--- /dev/null
+++ b/bash/settings.gradle
@@ -0,0 +1,2 @@
+rootProject.name = 'bash'
+
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/Controller.kt b/bash/src/main/kotlin/hse/nedikov/bash/Controller.kt
new file mode 100644
index 0000000..b26531a
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/Controller.kt
@@ -0,0 +1,41 @@
+package hse.nedikov.bash
+
+import hse.nedikov.bash.logic.Command
+import java.io.PipedReader
+import java.io.PipedWriter
+
+
+class Controller(val exceptionHandler: (Exception) -> Unit) {
+  private val env = Environment()
+
+  fun isWorking() = env.isWorking()
+
+  fun runCommandLine(line: String, outputHandler: (String) -> Unit) {
+    val tokens = Lexer(line, env.variables).lex()
+    val commands = parse(tokens, env)
+    val flow = makeFlow(commands);
+    flow.invoke().forEachLine { outputHandler(it) }
+  }
+
+  fun makeFlow(commands: ArrayList<Command>): () -> PipedReader =
+      if (commands.isEmpty()) {
+        { emptyCommandFlow() }
+      } else commandFlow(commands[0], commands.apply { removeAt(0) })
+
+  private fun commandFlow(command: Command, commands: ArrayList<Command>): () -> PipedReader = {
+    commands.reversed().fold(command.execute()) { reader, command ->
+      try {
+        command.execute(reader)
+      } catch (e: Exception) {
+        exceptionHandler(e)
+        emptyCommandFlow()
+      }
+    }
+  }
+
+  private fun emptyCommandFlow(): PipedReader {
+    val reader = PipedReader()
+    PipedWriter(reader).close()
+    return reader
+  }
+}
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/Environment.kt b/bash/src/main/kotlin/hse/nedikov/bash/Environment.kt
new file mode 100644
index 0000000..7176d9c
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/Environment.kt
@@ -0,0 +1,41 @@
+package hse.nedikov.bash
+
+import hse.nedikov.bash.Environment.State.*
+
+/**
+ * Environment of the interpreter
+ */
+class Environment {
+  private enum class State {
+    Working, Stop
+  }
+
+  private val varMap = HashMap<String, String>()
+  private var state: State = Working
+
+  /**
+   * Map of the local variables
+   */
+  val variables: (String) -> String = { name ->
+    varMap[name] ?: ""
+  }
+
+  /**
+   * Put the variable with value to the variables map
+   */
+  fun putVariable(name: String, value: String) {
+    varMap[name] = value
+  }
+
+  /**
+   * Changes state to the stop value
+   */
+  fun stopInterpreter() {
+    state = Stop
+  }
+
+  /**
+   * Returns true iff interpreter is still working
+   */
+  fun isWorking(): Boolean = state == Working
+}
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/Lexer.kt b/bash/src/main/kotlin/hse/nedikov/bash/Lexer.kt
new file mode 100644
index 0000000..7a19019
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/Lexer.kt
@@ -0,0 +1,161 @@
+package hse.nedikov.bash
+
+import hse.nedikov.bash.Lexer.ParserState.*
+import hse.nedikov.bash.exceptions.ParseException
+import java.lang.RuntimeException
+
+/**
+ * Lexer for bash interpreter
+ */
+class Lexer(private val data: String, private val variables: (String) -> String) {
+  enum class ParserState {
+    InDQuotes, InQuotes, Text, TextVariable, InDQuotesVariable, Identifier, Finished
+  }
+
+  private var state = Identifier
+  private var stringBuilder = StringBuilder()
+  private var varStringBuilder = StringBuilder()
+  private val result = ArrayList<String>()
+
+  /**
+   * Parse input to the tokens list
+   */
+  fun lex(): ArrayList<String> {
+    if (state == Finished) return result
+
+    for (x in data.withIndex()) {
+      val c = x.value
+      parseChar(c)
+    }
+    if (state == InDQuotes || state == InQuotes) {
+      throw ParseException("Quotes haven't closed")
+    }
+    if (varStringBuilder.isNotEmpty()) {
+      varStringBuilder = nextVariableBuilder(varStringBuilder, stringBuilder)
+    }
+    if (stringBuilder.isNotEmpty()) {
+      result.add(stringBuilder.toString())
+    }
+    state = Finished
+    return result
+  }
+
+  private fun parseChar(c: Char) {
+    when (state) {
+      Identifier -> parseIdentifierChar(c)
+      Text -> parseTextChar(c)
+      InQuotes -> parseInQuotesChar(c)
+      InDQuotes -> parseInDQuotesChar(c)
+      TextVariable -> parseVariableChar(c, Text)
+      InDQuotesVariable -> parseVariableChar(c, InDQuotes)
+      Finished -> throw RuntimeException("unexpected finished state")
+    }
+  }
+
+  private fun parseIdentifierChar(c: Char) {
+    when (c) {
+      matchIdentifier(c) -> stringBuilder.append(c)
+      matchDigit(c) -> {
+        if (stringBuilder.isNotEmpty()) stringBuilder.append(c)
+        else {
+          stringBuilder.append(c)
+          state = Text
+        }
+      }
+      '=' -> {
+        stringBuilder.append(c)
+        stringBuilder = nextBuilder(stringBuilder, result)
+        state = Text
+      }
+      in whiteSpaces -> {
+        if (stringBuilder.isNotEmpty()) {
+          state = Text
+          parseChar(c)
+        }
+      }
+      else -> {
+        state = Text
+        parseChar(c)
+      }
+    }
+  }
+
+  private fun parseVariableChar(c: Char, parent: ParserState) {
+    when (c) {
+      matchIdentifier(c) -> varStringBuilder.append(c)
+      matchDigit(c) -> {
+        if (varStringBuilder.isNotEmpty()) varStringBuilder.append(c)
+        else {
+          varStringBuilder = nextVariableBuilder(varStringBuilder, stringBuilder)
+          stringBuilder.append(c)
+          state = Text
+        }
+      }
+      else -> {
+        varStringBuilder = nextVariableBuilder(varStringBuilder, stringBuilder)
+        state = parent
+        parseChar(c)
+      }
+    }
+  }
+
+  private fun nextVariableBuilder(sb: StringBuilder, container: StringBuilder): StringBuilder {
+    container.append(variables(sb.toString()))
+    return StringBuilder()
+  }
+
+  private fun parseInDQuotesChar(c: Char) {
+    when (c) {
+      '"' -> {
+        stringBuilder = nextBuilder(stringBuilder, result)
+        state = Text
+      }
+      '$' -> state = InDQuotesVariable
+      else -> stringBuilder.append(c)
+    }
+  }
+
+  private fun parseInQuotesChar(c: Char) {
+    when (c) {
+      '\'' -> {
+        stringBuilder = nextBuilder(stringBuilder, result)
+        state = Text
+      }
+      else -> stringBuilder.append(c)
+    }
+  }
+
+  private fun parseTextChar(c: Char) {
+    when (c) {
+      in whiteSpaces -> {
+        if (stringBuilder.isNotEmpty()) {
+          stringBuilder = nextBuilder(stringBuilder, result)
+        }
+      }
+      '"' -> state = InDQuotes
+      '\'' -> state = InQuotes
+      '$' -> state = TextVariable
+      else -> stringBuilder.append(c)
+    }
+  }
+
+  companion object {
+    val whiteSpaces = Array(4) {
+      when (it) {
+        0 -> ' '
+        1 -> '\t'
+        2 -> '\n'
+        else -> '\r'
+      }
+    }
+
+    fun matchIdentifier(c: Char): Char = if (c in 'a'..'z' || c in 'z'..'Z' || c == '_' || c == '-') c else '_'
+
+    fun matchDigit(c: Char): Char = if (c in '0'..'9') c else '0'
+
+    fun nextBuilder(sb: StringBuilder, container: ArrayList<String>): StringBuilder {
+      container.add(sb.toString())
+      return StringBuilder()
+    }
+  }
+}
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/Main.kt b/bash/src/main/kotlin/hse/nedikov/bash/Main.kt
new file mode 100644
index 0000000..aaa0b76
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/Main.kt
@@ -0,0 +1,17 @@
+package hse.nedikov.bash
+
+object Main {
+  @JvmStatic
+  fun main(args: Array<String>) {
+    println("welcome!")
+    val errorHandler: (Exception) -> Unit = { println("error: ${it.message}") }
+    val controller = Controller(errorHandler)
+    while (controller.isWorking()) {
+      try {
+        controller.runCommandLine(readLine() ?: "") { println(it) }
+      } catch (e: java.lang.Exception) {
+        errorHandler(e)
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/Parser.kt b/bash/src/main/kotlin/hse/nedikov/bash/Parser.kt
new file mode 100644
index 0000000..d734c2f
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/Parser.kt
@@ -0,0 +1,33 @@
+package hse.nedikov.bash
+
+import hse.nedikov.bash.logic.Command
+
+private const val PIPE = "|"
+
+/**
+ * Creates a list of commands by string tokens in pipes
+ */
+fun parse(tokens: ArrayList<String>, env: Environment): ArrayList<Command> {
+  if (tokens.isNotEmpty() && tokens.last() == PIPE) {
+    throw Exception("$PIPE in end of command line")
+  }
+  val commands = ArrayList<Command>()
+  var i = 0;
+  while (i < tokens.size) {
+    val res = parseCommand(tokens, i, env)
+    i = res.first
+    commands.add(res.second)
+  }
+  return commands
+}
+
+private fun parseCommand(tokens: ArrayList<String>, start: Int, env: Environment): Pair<Int, Command> {
+  var i = start
+  val name = tokens[i++]
+  val args = ArrayList<String>()
+  while (i < tokens.size && tokens[i] != PIPE) {
+    args.add(tokens[i++])
+  }
+  return (i + 1) to Command.create(name, args, env)
+}
+
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/exceptions/ParseException.kt b/bash/src/main/kotlin/hse/nedikov/bash/exceptions/ParseException.kt
new file mode 100644
index 0000000..2d29147
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/exceptions/ParseException.kt
@@ -0,0 +1,8 @@
+package hse.nedikov.bash.exceptions
+
+import java.lang.Exception
+
+/**
+ * Exception for parser
+ */
+internal class ParseException(message: String) : Exception("Parse Exception: $message")
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/logic/Command.kt b/bash/src/main/kotlin/hse/nedikov/bash/logic/Command.kt
new file mode 100644
index 0000000..25eef02
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/logic/Command.kt
@@ -0,0 +1,58 @@
+package hse.nedikov.bash.logic
+
+import hse.nedikov.bash.Environment
+import hse.nedikov.bash.logic.commands.*
+import hse.nedikov.bash.logic.environment.Assign
+import hse.nedikov.bash.logic.environment.Exit
+import java.io.*
+
+/**
+ * Base class for all interpreter commands
+ */
+abstract class Command {
+  protected abstract fun execute(input: PipedReader, output: PipedWriter)
+  protected abstract fun execute(output: PipedWriter)
+
+  /**
+   * Execute the command uses the input. As result returns new reader, which is contains the output of the command
+   */
+  fun execute(input: PipedReader): PipedReader {
+    val reader = PipedReader()
+    val writer = PipedWriter(reader)
+    execute(input, writer)
+    writer.close()
+    return reader
+  }
+
+  /**
+   * Execute the command and returns new reader, which is contains the output of the command
+   */
+  fun execute(): PipedReader {
+    val reader = PipedReader()
+    val writer = PipedWriter(reader)
+    execute(writer)
+    writer.close()
+    return reader
+  }
+
+  companion object {
+    private val regex = Regex("[A-z_\\-][A-z_\\-0-9]*=")
+
+    /**
+     * Creates a command by name, environment and list of arguments
+     */
+    fun create(name: String, args: ArrayList<String>, env: Environment): Command {
+      if (regex.matches(name)) {
+        return Assign(name.take(name.length - 1), args, env)
+      }
+      return when (name) {
+        "echo" -> Echo(args)
+        "wc" -> WordCount(args)
+        "pwd" -> Pwd()
+        "exit" -> Exit(env)
+        "cat" -> Cat(args)
+        else -> OuterCommand(name, args)
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/logic/EnvironmentCommand.kt b/bash/src/main/kotlin/hse/nedikov/bash/logic/EnvironmentCommand.kt
new file mode 100644
index 0000000..69e7c33
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/logic/EnvironmentCommand.kt
@@ -0,0 +1,8 @@
+package hse.nedikov.bash.logic
+
+import hse.nedikov.bash.Environment
+
+/**
+ * Base class for commands which uses environment
+ */
+abstract class EnvironmentCommand(open val env: Environment) : Command()
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/Cat.kt b/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/Cat.kt
new file mode 100644
index 0000000..75c89d6
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/Cat.kt
@@ -0,0 +1,33 @@
+package hse.nedikov.bash.logic.commands
+
+import hse.nedikov.bash.logic.Command
+import java.io.*
+import java.lang.Exception
+
+/**
+ * cat command which prints files entries to the output stream
+ */
+class Cat(private val arguments: ArrayList<String>) : Command() {
+  /**
+   * Prints input to the output if has no arguments and prints entries of files from arguments otherwise
+   */
+  override fun execute(input: PipedReader, output: PipedWriter) {
+    if (arguments.isNotEmpty()) return execute(output)
+    input.forEachLine { output.write(it + System.lineSeparator()) }
+  }
+
+  /**
+   * Prints entries of files from arguments otherwise
+   */
+  override fun execute(output: PipedWriter) {
+    for (arg in arguments) {
+      try {
+        FileReader(arg).forEachLine { output.write(it + System.lineSeparator()) }
+      } catch (e: Exception) {
+        throw Exception("cat: ${e.message}")
+      }
+      output.write(System.lineSeparator())
+    }
+  }
+
+}
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/Echo.kt b/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/Echo.kt
new file mode 100644
index 0000000..b32f661
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/Echo.kt
@@ -0,0 +1,26 @@
+package hse.nedikov.bash.logic.commands
+
+import hse.nedikov.bash.logic.Command
+import java.io.*
+import java.util.*
+
+
+/**
+ * echo command which prints arguments to the output
+ */
+class Echo(private val arguments: ArrayList<String>) : Command() {
+  /**
+   * Prints arguments which are joined with spaces to the output
+   */
+  override fun execute(output: PipedWriter) {
+    val result = java.lang.String.join(" ", arguments)
+    output.write(result.toString())
+  }
+
+  /**
+   * Prints arguments which are joined with spaces to the output
+   */
+  override fun execute(input: PipedReader, output: PipedWriter) {
+    return execute(output)
+  }
+}
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/OuterCommand.kt b/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/OuterCommand.kt
new file mode 100644
index 0000000..d39457d
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/OuterCommand.kt
@@ -0,0 +1,62 @@
+package hse.nedikov.bash.logic.commands
+
+import hse.nedikov.bash.logic.Command
+import java.io.*
+import java.util.*
+import java.util.concurrent.Executors
+
+/**
+ * Class for calling commands in outer interpreter
+ * @param name name of the command
+ */
+class OuterCommand(private val name: String, private val arguments: ArrayList<String>) : Command() {
+  /**
+   * Calls the command in outer interpreter and print theirs output or error to the output
+   * in case when the command is executed in less than 10 seconds
+   */
+  override fun execute(input: PipedReader, output: PipedWriter) {
+    val process = createProcess()
+
+    val processWriter = OutputStreamWriter(process.outputStream)
+    input.readLines().forEach { processWriter.write(it + System.lineSeparator()) }
+    processWriter.flush()
+    processWriter.close()
+
+    startProcess(process, output)
+  }
+
+  /**
+   * Calls command in outer interpreter and print theirs output or error to the output
+   * in case when the command is executed in less than 10 seconds
+   */
+  private fun startProcess(process: Process, output: PipedWriter) {
+    val streamGobbler = StreamGobbler(process.inputStream) { s -> output.write(s + System.lineSeparator()) }
+    val errorGobbler = StreamGobbler(process.errorStream) { s -> output.write(s + System.lineSeparator()) }
+    val executor = Executors.newSingleThreadExecutor()
+    executor.submit(streamGobbler)
+    executor.submit(errorGobbler)
+    process.waitFor()
+    executor.shutdown()
+  }
+
+  override fun execute(output: PipedWriter) {
+    val process = createProcess()
+    startProcess(process, output)
+  }
+
+  private fun createProcess(): Process {
+    val environmentStart = if (isWindows) "cmd.exe /c" else "sh -c"
+    val command = StringJoiner(" ", "$name ", "").also { joiner -> arguments.forEach { joiner.add(it) } }.toString()
+    return Runtime.getRuntime().exec("$environmentStart $command")
+  }
+
+  private class StreamGobbler(private val inputStream: InputStream, private val consumer: (String) -> Unit) : Runnable {
+    override fun run() {
+      BufferedReader(InputStreamReader(inputStream)).lines().forEach(consumer)
+    }
+  }
+
+  companion object {
+    val isWindows = System.getProperty("os.name").toLowerCase().startsWith("windows")
+  }
+}
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/Pwd.kt b/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/Pwd.kt
new file mode 100644
index 0000000..990ccc3
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/Pwd.kt
@@ -0,0 +1,25 @@
+package hse.nedikov.bash.logic.commands
+
+import hse.nedikov.bash.logic.Command
+import java.io.*
+
+/**
+ * pwd command which prints current working directory
+ */
+class Pwd : Command() {
+  /**
+   * Prints current working directory to the output
+   */
+  override fun execute(input: PipedReader, output: PipedWriter) {
+    return execute(output)
+  }
+
+
+  /**
+   * Prints current working directory to the output
+   */
+  override fun execute(output: PipedWriter) {
+    output.write(System.getProperty("user.dir") + System.lineSeparator())
+  }
+
+}
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/WordCount.kt b/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/WordCount.kt
new file mode 100644
index 0000000..71a4de7
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/logic/commands/WordCount.kt
@@ -0,0 +1,61 @@
+package hse.nedikov.bash.logic.commands
+
+import hse.nedikov.bash.logic.Command
+import java.io.*
+import java.lang.Exception
+import java.util.*
+
+/**
+ * wc command which calculates count of lines, words and bytes in files or input
+ */
+class WordCount(private val arguments: ArrayList<String>) : Command() {
+  /**
+   * Calculates count of lines, words and bytes in input if arguments is empty and in files otherwise
+   */
+  override fun execute(input: PipedReader, output: PipedWriter) {
+    if (arguments.isNotEmpty()) {
+      return execute(output)
+    }
+    val r = calcInput(input)
+    output.write("${r.lines} ${r.words} ${r.bytes}" + System.lineSeparator())
+    output.close()
+  }
+
+  /**
+   * Calculates count of lines, words and bytes in files and prints results for each and in total
+   */
+  override fun execute(output: PipedWriter) {
+    val result = WCResult()
+    for (arg in arguments) {
+      try {
+        val r = calcInput(FileReader(arg))
+        output.write("${r.lines} ${r.words} ${r.bytes} $arg" + System.lineSeparator())
+        result += r
+      } catch (e: Exception) {
+        throw Exception("wc: ${e.message}" + System.lineSeparator())
+      }
+    }
+    output.write("${result.lines} ${result.words} ${result.bytes} total" + System.lineSeparator())
+  }
+
+  private fun calcInput(input: Reader): WCResult {
+    val result = WCResult()
+    val text = input.readText()
+    result.lines = text.split(Regex("\r\n|\r|\n")).size
+    result.words = StringTokenizer(text).countTokens()
+    result.bytes = text.toByteArray().size
+    return result
+  }
+
+  private class WCResult {
+    var lines = 0
+    var words = 0
+    var bytes = 0
+
+    operator fun plusAssign(other: WCResult) {
+      lines += other.lines
+      words += other.words
+      bytes += other.bytes
+    }
+  }
+}
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/logic/environment/Assign.kt b/bash/src/main/kotlin/hse/nedikov/bash/logic/environment/Assign.kt
new file mode 100644
index 0000000..ae66e21
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/logic/environment/Assign.kt
@@ -0,0 +1,30 @@
+package hse.nedikov.bash.logic.environment
+
+import hse.nedikov.bash.Environment
+import hse.nedikov.bash.logic.EnvironmentCommand
+import java.io.PipedReader
+import java.io.PipedWriter
+import java.lang.Exception
+
+/**
+ * Class for assigning of variables
+ * @param name name of variable
+ */
+class Assign(private val name:String, private val arguments: ArrayList<String>, override val env: Environment)
+  : EnvironmentCommand(env) {
+
+  /**
+   * Do nothing in this case
+   */
+  override fun execute(input: PipedReader, output: PipedWriter) {
+  }
+
+  /**
+   * Assigns the first argument to the variable in the environment
+   * @throws Exception if arguments list is empty
+   */
+  override fun execute(output: PipedWriter) {
+    if (arguments.isEmpty()) throw Exception("Assign exception: expected value after '='")
+    env.putVariable(name, arguments[0])
+  }
+}
\ No newline at end of file
diff --git a/bash/src/main/kotlin/hse/nedikov/bash/logic/environment/Exit.kt b/bash/src/main/kotlin/hse/nedikov/bash/logic/environment/Exit.kt
new file mode 100644
index 0000000..1c00c5a
--- /dev/null
+++ b/bash/src/main/kotlin/hse/nedikov/bash/logic/environment/Exit.kt
@@ -0,0 +1,24 @@
+package hse.nedikov.bash.logic.environment
+
+import hse.nedikov.bash.Environment
+import hse.nedikov.bash.logic.EnvironmentCommand
+import java.io.*
+
+/**
+ * Class for command which closes the interpreter
+ */
+class Exit(override val env: Environment) : EnvironmentCommand(env) {
+  /**
+   * Stops the interpreter
+   */
+  override fun execute(input: PipedReader, output: PipedWriter) {
+    return execute(output)
+  }
+
+  /**
+   * Stops the interpreter
+   */
+  override fun execute(output: PipedWriter) {
+    env.stopInterpreter()
+  }
+}
\ No newline at end of file
diff --git a/bash/src/test/kotlin/hse/nedikov/bash/LexerTest.kt b/bash/src/test/kotlin/hse/nedikov/bash/LexerTest.kt
new file mode 100644
index 0000000..24bae29
--- /dev/null
+++ b/bash/src/test/kotlin/hse/nedikov/bash/LexerTest.kt
@@ -0,0 +1,94 @@
+package hse.nedikov.bash
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class LexerTest {
+  @Test
+  fun lexEmptyString() {
+    val r = Lexer("") { _ -> "" }.lex()
+    assertEquals(0, r.size)
+  }
+
+  @Test
+  fun lexWord() {
+    val r = Lexer("lol") { _ -> "" }.lex()
+    assertEquals(1, r.size)
+    assertEquals("lol", r[0])
+  }
+
+  @Test
+  fun lexTwoWords() {
+    val r = Lexer("lol lal") { "" }.lex()
+    assertEquals(2, r.size)
+    assertEquals("lol", r[0])
+    assertEquals("lal", r[1])
+  }
+
+  @Test
+  fun lexVariable() {
+    val r = Lexer("\$lol", lolToLal).lex()
+    assertEquals(1, r.size)
+    assertEquals("lal", r[0])
+  }
+
+  @Test
+  fun lexVariable2() {
+    val r = Lexer("\$lol \$lel", lolToLal).lex()
+    assertEquals(1, r.size)
+    assertEquals("lal", r[0])
+  }
+
+  @Test
+  fun lexInQuotes() {
+    val r = Lexer("'lal lol '") { "" }.lex()
+    assertEquals(1, r.size)
+    assertEquals("lal lol ", r[0])
+  }
+
+  @Test
+  fun lexInDQuotes() {
+    val r = Lexer("\"lal lol \"") { "" }.lex()
+    assertEquals(1, r.size)
+    assertEquals("lal lol ", r[0])
+  }
+
+  @Test
+  fun lexInDQuotesWithVariable() {
+    val r = Lexer("\"lal \$lol \"", lolToLal).lex()
+    assertEquals(1, r.size)
+    assertEquals("lal lal ", r[0])
+  }
+
+  @Test
+  fun lexInQuotesWithVariable() {
+    val r = Lexer("'lal \$lol '", lolToLal).lex()
+    assertEquals(1, r.size)
+    assertEquals("lal \$lol ", r[0])
+  }
+
+  @Test
+  fun lexAssign() {
+    val r = Lexer("  lol=kek", lolToLal).lex()
+    assertEquals(2, r.size)
+    assertEquals("lol=", r[0])
+    assertEquals("kek", r[1])
+  }
+
+  @Test
+  fun lexAssignInQuotes() {
+    val r = Lexer("  lol='kek lol'", lolToLal).lex()
+    assertEquals(2, r.size)
+    assertEquals("lol=", r[0])
+    assertEquals("kek lol", r[1])
+  }
+
+  companion object {
+    val lolToLal: (String) -> String = {
+      when (it) {
+        "lol" -> "lal"
+        else -> ""
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/bash/src/test/kotlin/hse/nedikov/bash/ParserTest.kt b/bash/src/test/kotlin/hse/nedikov/bash/ParserTest.kt
new file mode 100644
index 0000000..1787054
--- /dev/null
+++ b/bash/src/test/kotlin/hse/nedikov/bash/ParserTest.kt
@@ -0,0 +1,49 @@
+package hse.nedikov.bash
+
+import hse.nedikov.bash.logic.commands.Echo
+import hse.nedikov.bash.logic.commands.WordCount
+import org.junit.Assert.*
+import org.junit.Test
+import java.util.*
+
+class ParserTest {
+  @Test
+  fun empty() {
+    assertTrue(parse(ArrayList(), environment).isEmpty())
+  }
+
+  @Test
+  fun simpleCommand() {
+    val result = parse(list("echo"), environment)
+    assertEquals(1, result.size)
+    assertTrue(result[0] is Echo)
+  }
+
+  @Test
+  fun commandWithArgs() {
+    val result = parse(list("echo", "lol", "kek"), environment)
+    assertEquals(1, result.size)
+    assertTrue(result[0] is Echo)
+  }
+
+  @Test
+  fun pipedCommands() {
+    val result = parse(list("echo", "|", "wc"), environment)
+    assertEquals(2, result.size)
+    assertTrue(result[0] is Echo)
+    assertTrue(result[1] is WordCount)
+  }
+
+
+  @Test
+  fun pipedCommandsWithArg() {
+    val result = parse(list("echo", "lol", "kek", "|", "wc", "cv"), environment)
+    assertEquals(2, result.size)
+    assertTrue(result[0] is Echo)
+    assertTrue(result[1] is WordCount)
+  }
+
+  companion object {
+    val environment = Environment()
+  }
+}
\ No newline at end of file
diff --git a/bash/src/test/kotlin/hse/nedikov/bash/TestUtil.kt b/bash/src/test/kotlin/hse/nedikov/bash/TestUtil.kt
new file mode 100644
index 0000000..8038f4a
--- /dev/null
+++ b/bash/src/test/kotlin/hse/nedikov/bash/TestUtil.kt
@@ -0,0 +1,5 @@
+package hse.nedikov.bash
+
+import java.util.ArrayList
+
+fun list(vararg values: String): ArrayList<String> = ArrayList<String>().apply { addAll(values) }
\ No newline at end of file
diff --git a/bash/src/test/kotlin/hse/nedikov/bash/logic/commands/CommandsTest.kt b/bash/src/test/kotlin/hse/nedikov/bash/logic/commands/CommandsTest.kt
new file mode 100644
index 0000000..5547648
--- /dev/null
+++ b/bash/src/test/kotlin/hse/nedikov/bash/logic/commands/CommandsTest.kt
@@ -0,0 +1,73 @@
+package hse.nedikov.bash.logic.commands
+
+import org.junit.Test
+import java.io.PipedReader
+import java.io.PipedWriter
+import java.util.*
+import hse.nedikov.bash.list
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+
+class CommandsTest {
+  @Test
+  fun echoSimple() {
+    val reader = Echo(list("lol")).execute()
+    assertEquals("lol", stringFromReader(reader))
+  }
+
+  @Test
+  fun echoMultiArguments() {
+    val reader = Echo(list("lol", "lal", "lel")).execute()
+    assertEquals("lol lal lel", stringFromReader(reader))
+  }
+
+  @Test
+  fun echoInputStream() {
+    val reader = Echo(list("lol", "lal", "lel")).execute(readerFromString("kekes"))
+    assertEquals("lol lal lel", stringFromReader(reader))
+  }
+
+  @Test
+  fun catSimple() {
+    val reader = Echo(list()).execute()
+    assertEquals("", stringFromReader(reader))
+  }
+
+  @Test
+  fun catInputStream() {
+    val reader = Cat(list()).execute(readerFromString("kekes leles"))
+    assertEquals("kekes leles", stringFromReader(reader))
+  }
+
+  @Test
+  fun pwdSimple() {
+    val reader = Pwd().execute()
+    assertTrue(stringFromReader(reader).isNotEmpty())
+  }
+
+  @Test
+  fun pwdSimpleWithInputStream() {
+    val reader = Pwd().execute(readerFromString("kekes leles"))
+    assertTrue(stringFromReader(reader).isNotEmpty())
+  }
+
+  @Test
+  fun wordCountSimple() {
+    val reader = WordCount(list()).execute(readerFromString(" lol kek   cheburek"))
+    assertEquals("1 3 19", stringFromReader(reader))
+  }
+
+  companion object {
+    fun readerFromString(string: String): PipedReader {
+      val reader = PipedReader()
+      PipedWriter(reader).apply { write(string) }.close()
+      return reader
+    }
+
+    fun stringFromReader(reader: PipedReader): String {
+      val joiner = StringJoiner(System.lineSeparator())
+      reader.readLines().forEach { joiner.add(it) }
+      return joiner.toString()
+    }
+  }
+}
\ No newline at end of file
diff --git a/bash/src/test/kotlin/hse/nedikov/bash/logic/environment/EnvironmentCommandsTest.kt b/bash/src/test/kotlin/hse/nedikov/bash/logic/environment/EnvironmentCommandsTest.kt
new file mode 100644
index 0000000..6f7f1e0
--- /dev/null
+++ b/bash/src/test/kotlin/hse/nedikov/bash/logic/environment/EnvironmentCommandsTest.kt
@@ -0,0 +1,30 @@
+package hse.nedikov.bash.logic.environment
+
+import hse.nedikov.bash.Environment
+import hse.nedikov.bash.list
+import org.junit.Assert.*
+import org.junit.Before
+import org.junit.Test
+
+class EnvironmentCommandsTest {
+  lateinit var environment: Environment
+  @Before
+  fun createEnvironment() {
+    environment = Environment()
+    environment.putVariable("x", "lel")
+  }
+
+  @Test
+  fun testAssign() {
+    assertEquals("lel", environment.variables("x"))
+    Assign("x", list("lal"), environment).execute()
+    assertEquals("lal", environment.variables("x"))
+  }
+
+  @Test
+  fun testExit() {
+    assertTrue(environment.isWorking())
+    Exit(environment).execute()
+    assertFalse(environment.isWorking())
+  }
+}
\ No newline at end of file
diff --git a/build.sh b/build.sh
new file mode 100644
index 0000000..a983b02
--- /dev/null
+++ b/build.sh
@@ -0,0 +1,9 @@
+#! /bin/bash
+
+for hw in $(find . -maxdepth 1 -mindepth 1 -type d) ; do
+    if [ -f "$hw/build.gradle" ] ; then
+        echo "processing $hw"
+        cd "$hw" && gradle check && cd .. || { echo "check failed" ; exit 1 ; }
+        echo "finishing $hw"
+    fi
+done
\ No newline at end of file