diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..c405483
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,10 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+indent_style = space
+insert_final_newline = false
+max_line_length = 120
+tab_width = 8
diff --git a/.github/workflows/gradle.yml b/.github/workflows/gradle.yml
new file mode 100755
index 0000000..74ba1e7
--- /dev/null
+++ b/.github/workflows/gradle.yml
@@ -0,0 +1,16 @@
+name: CI
+on: [push]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK 17
+        uses: actions/setup-java@v2
+        with:
+          java-version: 17
+          distribution: 'adopt'
+      - name: Build with Gradle
+        run: ./gradlew build
+      - name: Test with Gradle
+        run: ./gradlew test
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..12ddda9
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+build
+.gradle
+.idea
diff --git a/README.md b/README.md
index 1ec6ae4..8a3d0bd 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,25 @@
-# sd-homework
\ No newline at end of file
+# simplecli
+
+### How to run
+
+Run [main](src/main/java/ru/itmo/simplecli/Main.java)
+method from IDE **or** `./gradlew run`.
+
+### What's there
+
+Implemented build-ins:
+- [cat](src/main/java/ru/itmo/simplecli/executor/commands/Cat.java)
+- [echo](src/main/java/ru/itmo/simplecli/executor/commands/Echo.java)
+- [exit](src/main/java/ru/itmo/simplecli/executor/commands/Exit.java)
+- [pwd](src/main/java/ru/itmo/simplecli/executor/commands/Pwd.java)
+- [wc](src/main/java/ru/itmo/simplecli/executor/commands/WC.java)
+- [variable assignment](src/main/java/ru/itmo/simplecli/executor/commands/Assignment.java)
+
+[Main](src/main/java/ru/itmo/simplecli/Main.java) runs loop until `exit` command is given.
+If the entered string contains incomplete quotes, it asks to continue typing.
+
+[Parser](src/main/java/ru/itmo/simplecli/executor/Parser.java) supports double and single quotes.
+It also performs substitution for values beginning with `$` if it is not surrounded by single quotes.
+
+The CLI [supports](src/main/java/ru/itmo/simplecli/executor/PipedCommand.java) a pipeline of commands, separated by a sign `|`,
+each command receives as input the output of the previous one.
\ No newline at end of file
diff --git a/build.gradle.kts b/build.gradle.kts
new file mode 100644
index 0000000..e175653
--- /dev/null
+++ b/build.gradle.kts
@@ -0,0 +1,34 @@
+plugins {
+    application
+}
+
+application {
+    mainClass.set("ru.itmo.simplecli.Main")
+}
+
+group = "ru.itmo"
+version = "1.0"
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation("commons-cli:commons-cli:1.5.0")
+    testImplementation("org.junit.jupiter:junit-jupiter-api:5.8.2")
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine")
+}
+
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(17))
+    }
+}
+
+tasks.test {
+    useJUnitPlatform()
+}
+
+tasks.named<JavaExec>("run") {
+    standardInput = System.`in`
+}
\ 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..7454180
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..ffed3a2
--- /dev/null
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
new file mode 100755
index 0000000..744e882
--- /dev/null
+++ b/gradlew
@@ -0,0 +1,185 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  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 "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MSYS* | MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$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 or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; 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=`expr $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"
+
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
new file mode 100644
index 0000000..ac1b06f
--- /dev/null
+++ b/gradlew.bat
@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@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 Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@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="-Xmx64m" "-Xms64m"
+
+@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 execute
+
+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 execute
+
+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
+
+: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 %*
+
+: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/settings.gradle.kts b/settings.gradle.kts
new file mode 100644
index 0000000..e895432
--- /dev/null
+++ b/settings.gradle.kts
@@ -0,0 +1,2 @@
+rootProject.name = "simplecli"
+
diff --git a/src/main/java/ru/itmo/simplecli/Main.java b/src/main/java/ru/itmo/simplecli/Main.java
new file mode 100644
index 0000000..63d37a8
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/Main.java
@@ -0,0 +1,53 @@
+package ru.itmo.simplecli;
+
+import ru.itmo.simplecli.executor.*;
+
+import java.io.PrintStream;
+import java.util.*;
+
+/**
+ * Entry point. Loop: read - parse - execute.
+ */
+public class Main {
+    private static final Scanner input = new Scanner(System.in);
+    private static final PrintStream output = new PrintStream(System.out);
+    private static final AbstractCommandFactory commandFactory = new PipedCommandFactory();
+
+    public static void main(String[] args) {
+        EnvironmentManager environment = new EnvironmentManager();
+        Parser parser = new Parser(environment);
+
+        while (true) {
+            output.print(">> ");
+            String nextLine = input.nextLine();
+            if (nextLine.trim().equals("")) {
+                continue;
+            }
+
+            parser.parse(nextLine);
+            while (parser.hasUnclosedQuote()) {
+                output.print("> ");
+                nextLine = nextLine + input.nextLine();
+                parser.parse(nextLine);
+            }
+
+            if (parser.getResult().equals(List.of(""))) {
+                continue;
+            }
+
+            var command = commandFactory.construct(parser.getResult(), environment);
+            if (command == null) {
+                output.println("Can't construct command");
+                continue;
+            }
+
+            command.execute(null);
+            if (command.getEndStatus() == Executable.EndStatus.EXIT) {
+                break;
+            }
+            if (command.getOutput() != null) {
+                output.println(command.getOutput());
+            }
+        }
+    }
+}
diff --git a/src/main/java/ru/itmo/simplecli/executor/AbstractCommandFactory.java b/src/main/java/ru/itmo/simplecli/executor/AbstractCommandFactory.java
new file mode 100644
index 0000000..42a9a81
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/AbstractCommandFactory.java
@@ -0,0 +1,15 @@
+package ru.itmo.simplecli.executor;
+
+import java.util.List;
+import java.util.regex.Pattern;
+
+public abstract class AbstractCommandFactory {
+    public abstract Executable construct(List<String> args, EnvironmentManager environment);
+
+    protected boolean isAssignment(List<String> args) {
+        return args.size() == 3
+            && Pattern.matches("\\w+", args.get(0))
+            && args.get(1).equals("=")
+            && Pattern.matches("\\w+", args.get(2));
+    }
+}
diff --git a/src/main/java/ru/itmo/simplecli/executor/EnvironmentManager.java b/src/main/java/ru/itmo/simplecli/executor/EnvironmentManager.java
new file mode 100644
index 0000000..4acdc40
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/EnvironmentManager.java
@@ -0,0 +1,36 @@
+package ru.itmo.simplecli.executor;
+
+import java.util.HashMap;
+
+/**
+ * Class for local environment
+ */
+public class EnvironmentManager {
+    private final HashMap<String, String> environment = new HashMap<>();
+
+    /**
+     * If there is no local variable uses global environment
+     *
+     * @param name name of the variable
+     * @return value of the variable
+     */
+    public final String get(String name) {
+        if (environment.containsKey(name)) {
+            return environment.get(name);
+        }
+        if (System.getenv().containsKey(name)) {
+            return System.getenv(name);
+        }
+        return "";
+    }
+
+    /**
+     * Set or rewrites variable value
+     *
+     * @param name  name of a variable
+     * @param value value of a variable
+     */
+    public final void set(String name, String value) {
+        environment.put(name, value);
+    }
+}
diff --git a/src/main/java/ru/itmo/simplecli/executor/Executable.java b/src/main/java/ru/itmo/simplecli/executor/Executable.java
new file mode 100644
index 0000000..4306b91
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/Executable.java
@@ -0,0 +1,29 @@
+package ru.itmo.simplecli.executor;
+
+/**
+ * Class for anything that can be executed
+ */
+public interface Executable {
+    /**
+     * Executes with the given input
+     *
+     * @param input
+     */
+    void execute(String input);
+
+    /**
+     * @return result of execution or error message
+     */
+    String getOutput();
+
+    /**
+     * @return status of execution
+     */
+    EndStatus getEndStatus();
+
+    enum EndStatus {
+        SUCCESS,
+        ERROR,
+        EXIT
+    }
+}
diff --git a/src/main/java/ru/itmo/simplecli/executor/Parser.java b/src/main/java/ru/itmo/simplecli/executor/Parser.java
new file mode 100644
index 0000000..0816475
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/Parser.java
@@ -0,0 +1,147 @@
+package ru.itmo.simplecli.executor;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Simple parser that handles single and double quotes
+ */
+public class Parser {
+    private final EnvironmentManager environment;
+    private List<Wrapped> result;
+    private State state;
+
+    public Parser(EnvironmentManager environment) {
+        this.environment = environment;
+    }
+
+    /**
+     * @param input string that contains command with args
+     */
+    public void parse(String input) {
+        result = new ArrayList<>();
+        state = State.NO_QUOTED;
+        runParse(input);
+    }
+
+    /**
+     * @return result of parsing
+     */
+    public List<String> getResult() {
+        return result.stream().map(Wrapped::getValue).toList();
+    }
+
+    /**
+     * @return value if input string had proper quotes
+     */
+    public boolean hasUnclosedQuote() {
+        return state != State.NO_QUOTED;
+    }
+
+    private void runParse(String string) {
+        StringBuilder current = new StringBuilder();
+        for (int pos = 0; pos < string.length(); pos++) {
+            var symbol = string.charAt(pos);
+
+            if (state == State.SINGLE_QUOTED) {
+                if (symbol == '\'') {
+                    result.add(new SingleQuoted(current));
+                    current = new StringBuilder();
+                    state = State.NO_QUOTED;
+                } else {
+                    current.append(symbol);
+                }
+            } else if (state == State.DOUBLE_QUOTED) {
+                if (symbol == '"') {
+                    result.add(new DoubleQuoted(current));
+                    current = new StringBuilder();
+                    state = State.NO_QUOTED;
+                } else {
+                    current.append(symbol);
+                }
+            } else {
+                if (symbol == ' ') {
+                    if (!current.isEmpty()) {
+                        result.add(new Wrapped(current));
+                        current = new StringBuilder();
+                    }
+                } else if (symbol == '|' || symbol == '=') {
+                    if (!current.isEmpty()) {
+                        result.add(new Wrapped(current));
+                        current = new StringBuilder();
+                    }
+                    result.add(new Wrapped(new StringBuilder().append(symbol)));
+                } else if (symbol == '\'') {
+                    if (!current.isEmpty()) {
+                        result.add(new Wrapped(current));
+                        current = new StringBuilder();
+                    }
+                    state = State.SINGLE_QUOTED;
+                } else if (symbol == '"') {
+                    if (!current.isEmpty()) {
+                        result.add(new Wrapped(current));
+                        current = new StringBuilder();
+                    }
+                    state = State.DOUBLE_QUOTED;
+                } else {
+                    current.append(symbol);
+                }
+            }
+        }
+        if (state == State.NO_QUOTED && !current.isEmpty()) {
+            result.add(new Wrapped(current));
+        }
+    }
+
+    private enum State {
+        NO_QUOTED,
+        DOUBLE_QUOTED,
+        SINGLE_QUOTED
+    }
+
+    private class Wrapped {
+        protected StringBuilder value;
+
+        Wrapped(StringBuilder value) {
+            this.value = value;
+        }
+
+        public String getValue() {
+            if (value.indexOf("$") == -1) {
+                return value.toString();
+            }
+            var start = value.indexOf("$");
+            var end = start + 1;
+            while (end < value.length()) {
+                var symbol = value.charAt(end);
+                if (!Character.isAlphabetic(symbol)
+                    && !Character.isDigit(symbol)
+                    && !(symbol == '_')) {
+                    break;
+                }
+                end++;
+            }
+            var varName = value.substring(start + 1, end);
+            value.delete(start, end);
+            value.insert(start, environment.get(varName));
+            return getValue();
+        }
+    }
+
+    private class SingleQuoted extends Wrapped {
+        SingleQuoted(StringBuilder value) {
+            super(value);
+        }
+
+        @Override
+        public String getValue() {
+            return value.toString();
+        }
+    }
+
+    private class DoubleQuoted extends Wrapped {
+        DoubleQuoted(StringBuilder value) {
+            super(value);
+        }
+    }
+}
diff --git a/src/main/java/ru/itmo/simplecli/executor/PipedCommand.java b/src/main/java/ru/itmo/simplecli/executor/PipedCommand.java
new file mode 100644
index 0000000..120ca8a
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/PipedCommand.java
@@ -0,0 +1,39 @@
+package ru.itmo.simplecli.executor;
+
+import java.util.List;
+
+/**
+ * Piped command executes every command, pass output of one as input to the next one
+ */
+class PipedCommand implements Executable {
+    private final List<Executable> executables;
+    private EndStatus status;
+    private String output;
+
+    public PipedCommand(List<Executable> executables) {
+        this.executables = executables;
+    }
+
+    @Override
+    public void execute(String input) {
+        output = input;
+        for (var executable : executables) {
+            executable.execute(output);
+            output = executable.getOutput();
+            status = executable.getEndStatus();
+            if (status != EndStatus.SUCCESS) {
+                return;
+            }
+        }
+    }
+
+    @Override
+    public String getOutput() {
+        return output;
+    }
+
+    @Override
+    public EndStatus getEndStatus() {
+        return status;
+    }
+}
diff --git a/src/main/java/ru/itmo/simplecli/executor/PipedCommandFactory.java b/src/main/java/ru/itmo/simplecli/executor/PipedCommandFactory.java
new file mode 100644
index 0000000..a3da42a
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/PipedCommandFactory.java
@@ -0,0 +1,41 @@
+package ru.itmo.simplecli.executor;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.NavigableSet;
+
+/**
+ * Class to construct piped commands
+ */
+public class PipedCommandFactory extends AbstractCommandFactory {
+
+    @Override
+    public Executable construct(List<String> args, EnvironmentManager environment) {
+        var lists = splitIntoCommands(args);
+        var executables = new ArrayList<Executable>();
+        var singleCommandFactory = new SingleCommandFactory();
+        for (var list : lists) {
+            var cmd = singleCommandFactory.construct(list, environment);
+            if (cmd == null) {
+                return null;
+            }
+            executables.add(cmd);
+        }
+        return new PipedCommand(executables);
+    }
+
+    private List<List<String>> splitIntoCommands(List<String> args) {
+        List<List<String>> result = new ArrayList<>();
+        List<String> current = new ArrayList<>();
+        for (var element : args) {
+            if (element.equals("|")) {
+                result.add(current);
+                current = new ArrayList<>();
+            } else {
+                current.add(element);
+            }
+        }
+        result.add(current);
+        return result;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/ru/itmo/simplecli/executor/SingleCommandFactory.java b/src/main/java/ru/itmo/simplecli/executor/SingleCommandFactory.java
new file mode 100644
index 0000000..fdbd66f
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/SingleCommandFactory.java
@@ -0,0 +1,31 @@
+package ru.itmo.simplecli.executor;
+
+import ru.itmo.simplecli.executor.commands.*;
+
+import java.util.List;
+import java.util.regex.Pattern;
+
+/**
+ * Class to construct commands
+ */
+public class SingleCommandFactory extends AbstractCommandFactory {
+    @Override
+    public Executable construct(List<String> args, EnvironmentManager environment) {
+        if (args.size() == 0) {
+            return null;
+        }
+        if (isAssignment(args)) {
+            return new Assignment(args, environment);
+        }
+        var name = args.get(0);
+        return switch (name) {
+            case "cat" -> new Cat(args.subList(1, args.size()), environment);
+            case "echo" -> new Echo(args.subList(1, args.size()), environment);
+            case "exit" -> new Exit(args.subList(1, args.size()), environment);
+            case "pwd" -> new Pwd(args.subList(1, args.size()), environment);
+            case "wc" -> new WC(args.subList(1, args.size()), environment);
+            default -> new External(args, environment);
+        };
+    }
+
+}
diff --git a/src/main/java/ru/itmo/simplecli/executor/commands/Assignment.java b/src/main/java/ru/itmo/simplecli/executor/commands/Assignment.java
new file mode 100644
index 0000000..fc10688
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/commands/Assignment.java
@@ -0,0 +1,20 @@
+package ru.itmo.simplecli.executor.commands;
+
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.util.List;
+
+/**
+ * Changes local variable value
+ */
+public class Assignment extends Command {
+    public Assignment(List<String> args, EnvironmentManager environment) {
+        super(args, environment);
+    }
+
+    @Override
+    public void execute(String input) {
+        environment.set(args.get(0), args.get(2));
+        status = EndStatus.SUCCESS;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/ru/itmo/simplecli/executor/commands/Cat.java b/src/main/java/ru/itmo/simplecli/executor/commands/Cat.java
new file mode 100644
index 0000000..24d125d
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/commands/Cat.java
@@ -0,0 +1,58 @@
+package ru.itmo.simplecli.executor.commands;
+
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.StringReader;
+import java.util.List;
+
+/**
+ * Concatenates given files content
+ */
+public class Cat extends Command {
+
+
+    public Cat(List<String> args, EnvironmentManager environment) {
+        super(args, environment);
+    }
+
+    @Override
+    public void execute(String input) {
+        if (args.size() == 0 && input == null) {
+            status = EndStatus.ERROR;
+            output = "Not enough arguments for `cat` command";
+            return;
+        }
+
+        if (args.size() == 0) {
+            output = handle(new BufferedReader(new StringReader(input)));
+            status = EndStatus.SUCCESS;
+            return;
+        }
+
+        try {
+            var sb = new StringBuilder();
+            for (var arg : args) {
+                var file = new BufferedReader(new FileReader(arg));
+                sb.append(handle(file));
+            }
+            output = sb.toString();
+            status = EndStatus.SUCCESS;
+        } catch (IOException e) {
+            status = EndStatus.ERROR;
+            output = e.getMessage();
+        }
+
+    }
+
+    private String handle(BufferedReader file) {
+        var sb = new StringBuilder();
+        for (var line : file.lines().toList()) {
+            sb.append(line).append("\n");
+        }
+        return sb.toString();
+    }
+
+}
\ No newline at end of file
diff --git a/src/main/java/ru/itmo/simplecli/executor/commands/Command.java b/src/main/java/ru/itmo/simplecli/executor/commands/Command.java
new file mode 100644
index 0000000..a0548d1
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/commands/Command.java
@@ -0,0 +1,35 @@
+package ru.itmo.simplecli.executor.commands;
+
+import ru.itmo.simplecli.executor.EnvironmentManager;
+import ru.itmo.simplecli.executor.Executable;
+
+import java.util.List;
+
+/**
+ * Abstract class for an explicit command
+ */
+public abstract class Command implements Executable {
+    protected EndStatus status;
+    protected List<String> args;
+    protected String output = null;
+    protected EnvironmentManager environment;
+
+    public Command(List<String> args, EnvironmentManager environment) {
+        this.args = args;
+        this.environment = environment;
+    }
+
+    @Override
+    public String getOutput() {
+        return output;
+    }
+
+    @Override
+    public EndStatus getEndStatus() {
+        return status;
+    }
+
+    @Override
+    public abstract void execute(String input);
+
+}
\ No newline at end of file
diff --git a/src/main/java/ru/itmo/simplecli/executor/commands/Echo.java b/src/main/java/ru/itmo/simplecli/executor/commands/Echo.java
new file mode 100644
index 0000000..67df190
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/commands/Echo.java
@@ -0,0 +1,22 @@
+package ru.itmo.simplecli.executor.commands;
+
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.util.List;
+
+/**
+ * Returns given args without changes
+ */
+public class Echo extends Command {
+
+    public Echo(List<String> args, EnvironmentManager environment) {
+        super(args, environment);
+    }
+
+    @Override
+    public void execute(String input) {
+        output = String.join(" ", args);
+        status = EndStatus.SUCCESS;
+    }
+
+}
\ No newline at end of file
diff --git a/src/main/java/ru/itmo/simplecli/executor/commands/Exit.java b/src/main/java/ru/itmo/simplecli/executor/commands/Exit.java
new file mode 100644
index 0000000..8290296
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/commands/Exit.java
@@ -0,0 +1,21 @@
+package ru.itmo.simplecli.executor.commands;
+
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.util.List;
+
+/**
+ * Exits application
+ */
+public class Exit extends Command {
+
+    public Exit(List<String> args, EnvironmentManager environment) {
+        super(args, environment);
+    }
+
+    @Override
+    public void execute(String input) {
+        status = EndStatus.EXIT;
+    }
+
+}
diff --git a/src/main/java/ru/itmo/simplecli/executor/commands/External.java b/src/main/java/ru/itmo/simplecli/executor/commands/External.java
new file mode 100644
index 0000000..07795d9
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/commands/External.java
@@ -0,0 +1,44 @@
+package ru.itmo.simplecli.executor.commands;
+
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+
+/**
+ * Class for not build-ins command
+ */
+public class External extends Command {
+
+    public External(List<String> args, EnvironmentManager environment) {
+        super(args, environment);
+    }
+
+    @Override
+    public void execute(String input) {
+        try {
+            var process = new ProcessBuilder(args).start();
+            if (input != null) {
+                var stream = process.getOutputStream();
+                stream.write(input.getBytes(StandardCharsets.UTF_8));
+                stream.close();
+            }
+            var exitCode = process.waitFor();
+            var sb = new StringBuilder();
+            var stream = exitCode == 0 ? process.getInputStream() : process.getErrorStream();
+            var reader = new BufferedReader(new InputStreamReader(stream));
+            String line;
+            while ((line = reader.readLine()) != null) {
+                sb.append(line).append("\n");
+            }
+            output = sb.toString();
+            status = exitCode == 0 ? EndStatus.SUCCESS : EndStatus.ERROR;
+        } catch (IOException | InterruptedException e) {
+            status = EndStatus.ERROR;
+            output = e.getMessage();
+        }
+    }
+}
diff --git a/src/main/java/ru/itmo/simplecli/executor/commands/Pwd.java b/src/main/java/ru/itmo/simplecli/executor/commands/Pwd.java
new file mode 100644
index 0000000..7f1ab5c
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/commands/Pwd.java
@@ -0,0 +1,21 @@
+package ru.itmo.simplecli.executor.commands;
+
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.util.List;
+
+/**
+ * Returns PWD value
+ */
+public class Pwd extends Command {
+
+    public Pwd(List<String> args, EnvironmentManager environment) {
+        super(args, environment);
+    }
+
+    @Override
+    public void execute(String string) {
+        output = System.getProperty("user.dir");
+        status = EndStatus.SUCCESS;
+    }
+}
diff --git a/src/main/java/ru/itmo/simplecli/executor/commands/WC.java b/src/main/java/ru/itmo/simplecli/executor/commands/WC.java
new file mode 100644
index 0000000..2058569
--- /dev/null
+++ b/src/main/java/ru/itmo/simplecli/executor/commands/WC.java
@@ -0,0 +1,79 @@
+package ru.itmo.simplecli.executor.commands;
+
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.StringReader;
+import java.util.List;
+
+/**
+ * Counts number of lines, symbols and bytes for every given file
+ */
+public class WC extends Command {
+
+    public WC(List<String> args, EnvironmentManager environment) {
+        super(args, environment);
+    }
+
+    @Override
+    public void execute(String input) {
+        if (args.size() == 0 && input == null) {
+            status = EndStatus.ERROR;
+            output = "Not enough arguments for `wc` command";
+            return;
+        }
+        try {
+            if (args.size() == 0) {
+                var reader = new BufferedReader(new StringReader(input));
+                output = handle(reader, "").toString();
+            } else {
+                int totalLines = 0, totalWords = 0, totalBytes = 0;
+                var builder = new StringBuilder();
+                for (var arg : args) {
+                    var file = new BufferedReader(new FileReader(arg));
+                    var result = handle(file, arg);
+                    totalLines += result.lines;
+                    totalWords += result.words;
+                    totalBytes += result.bytes;
+                    builder.append(result);
+                }
+                if (args.size() > 1) {
+                    builder.append(new ResultLine(totalLines, totalWords, totalBytes, "total"));
+                }
+                output = builder.toString();
+            }
+            status = EndStatus.SUCCESS;
+        } catch (IOException e) {
+            status = EndStatus.ERROR;
+            output = e.getMessage();
+        }
+    }
+
+    private ResultLine handle(BufferedReader file, String name) throws IOException {
+        int lines = 0, words = 0, bytes = 0;
+        int prev = ' ', c;
+        while ((c = file.read()) != -1) {
+            bytes += 1;
+            if ((char) c == '\n') {
+                lines += 1;
+            }
+            if (Character.isWhitespace(prev) && !Character.isWhitespace(c)) {
+                words += 1;
+            }
+            prev = c;
+        }
+        return new ResultLine(lines, words, bytes, name);
+    }
+
+    private record ResultLine(int lines, int words, int bytes, String name) {
+        public String toString() {
+            return lines + "\t" +
+                words + "\t" +
+                bytes + "\t" +
+                name +
+                "\n";
+        }
+    }
+}
diff --git a/src/test/java/ru/itmo/simplecli/executor/ParserTest.java b/src/test/java/ru/itmo/simplecli/executor/ParserTest.java
new file mode 100644
index 0000000..151fc02
--- /dev/null
+++ b/src/test/java/ru/itmo/simplecli/executor/ParserTest.java
@@ -0,0 +1,74 @@
+package ru.itmo.simplecli.executor;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.Objects;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class ParserTest {
+
+    private final EnvironmentManager env = new EnvironmentManager();
+    private final Parser parser = new Parser(env);
+
+    @Test
+    public void testLonelyCommand() {
+        parser.parse("cat file1 file2");
+        assertEquals(parser.getResult(), List.of("cat", "file1", "file2"));
+
+        parser.parse("echo input");
+        assertEquals(parser.getResult(), List.of("echo", "input"));
+
+        parser.parse("exit");
+        assertEquals(parser.getResult(), List.of("exit"));
+
+        parser.parse("grep -i -w -A 10 pattern file1 file2");
+        assertEquals(parser.getResult(),
+            List.of("grep", "-i", "-w", "-A", "10", "pattern", "file1", "file2"));
+
+        parser.parse("pwd");
+        assertEquals(parser.getResult(), List.of("pwd"));
+
+        parser.parse("wc file1 file2");
+        assertEquals(parser.getResult(), List.of("wc", "file1", "file2"));
+    }
+
+    @Test
+    public void testExtraSpaces() {
+        parser.parse("cmd     arg1     arg2");
+        assertEquals(parser.getResult(), List.of("cmd", "arg1", "arg2"));
+    }
+
+    @Test
+    public void testDoubleQuoted() {
+        parser.parse("cmd \"arg1\" \" arg2\" ");
+        assertEquals(parser.getResult(), List.of("cmd", "arg1", " arg2"));
+
+        parser.parse("cmd \"arg");
+        assertTrue(parser.hasUnclosedQuote());
+
+        parser.parse(" \"$PWD\" ");
+        assertEquals(parser.getResult(), List.of(Objects.requireNonNull(env.get("PWD"))));
+    }
+
+    @Test
+    public void testSingleQuoted() {
+        parser.parse("cmd 'arg1' ' arg2' ");
+        assertEquals(parser.getResult(), List.of("cmd", "arg1", " arg2"));
+
+        parser.parse("cmd 'arg");
+        assertTrue(parser.hasUnclosedQuote());
+
+        parser.parse(" '$PWD' ");
+        assertEquals(parser.getResult(), List.of("$PWD"));
+    }
+
+    @Test
+    public void testPiped() {
+        parser.parse(" cmd1 arg  |  cmd2 arg |  cmd3 arg ");
+        assertEquals(parser.getResult(),
+            List.of("cmd1", "arg", "|", "cmd2", "arg", "|", "cmd3", "arg"));
+    }
+}
\ No newline at end of file
diff --git a/src/test/java/ru/itmo/simplecli/executor/PipedCommandFactoryTest.java b/src/test/java/ru/itmo/simplecli/executor/PipedCommandFactoryTest.java
new file mode 100644
index 0000000..5d125c9
--- /dev/null
+++ b/src/test/java/ru/itmo/simplecli/executor/PipedCommandFactoryTest.java
@@ -0,0 +1,25 @@
+package ru.itmo.simplecli.executor;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+public class PipedCommandFactoryTest {
+
+    public AbstractCommandFactory instance = new PipedCommandFactory();
+
+    @Test
+    public void testPipe() {
+        var env = new EnvironmentManager();
+        var args = List.of(
+            "cat", "|", "echo", "|", "grep", "|", "exit", "|", "pwd", "|", "wc"
+        );
+        assertNotNull(instance.construct(args, env));
+        assertNull(instance.construct(List.of(), env));
+    }
+
+}
\ No newline at end of file
diff --git a/src/test/java/ru/itmo/simplecli/executor/SingleCommandFactoryTest.java b/src/test/java/ru/itmo/simplecli/executor/SingleCommandFactoryTest.java
new file mode 100644
index 0000000..5dcc4e2
--- /dev/null
+++ b/src/test/java/ru/itmo/simplecli/executor/SingleCommandFactoryTest.java
@@ -0,0 +1,65 @@
+package ru.itmo.simplecli.executor;
+
+import org.junit.jupiter.api.Test;
+import ru.itmo.simplecli.executor.commands.*;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+public class SingleCommandFactoryTest {
+    private final AbstractCommandFactory instance = new SingleCommandFactory();
+    public EnvironmentManager env = new EnvironmentManager();
+
+    @Test
+    public void testCatImplemented() {
+        var args = List.of("cat");
+        assertEquals(Objects.requireNonNull(instance.construct(args, env)).getClass(),
+            Cat.class);
+    }
+
+    @Test
+    public void testEchoImplemented() {
+        var args = List.of("echo");
+        assertEquals(Objects.requireNonNull(instance.construct(args, env)).getClass(),
+            Echo.class);
+    }
+
+    @Test
+    public void testExitImplemented() {
+        var args = List.of("exit");
+        assertEquals(Objects.requireNonNull(instance.construct(args, env)).getClass(),
+            Exit.class);
+    }
+
+    @Test
+    public void testPwdImplemented() {
+        var args = List.of("pwd");
+        assertEquals(Objects.requireNonNull(instance.construct(args, env)).getClass(),
+            Pwd.class);
+    }
+
+    @Test
+    public void testWCImplemented() {
+        var args = List.of("wc");
+        assertEquals(Objects.requireNonNull(instance.construct(args, env)).getClass(),
+            WC.class);
+    }
+
+    @Test
+    public void testExternalImplemented() {
+        var args = List.of("unknowncommand");
+        assertEquals(Objects.requireNonNull(instance.construct(args, env)).getClass(),
+            External.class);
+
+        assertNull(instance.construct(new ArrayList<>(), env));
+    }
+
+    @Test
+    public void testConstructorWithEmptyInput() {
+        assertNull(instance.construct(new ArrayList<>(), env));
+    }
+}
\ No newline at end of file
diff --git a/src/test/java/ru/itmo/simplecli/executor/commands/AbstractCommandTest.java b/src/test/java/ru/itmo/simplecli/executor/commands/AbstractCommandTest.java
new file mode 100644
index 0000000..ff675f8
--- /dev/null
+++ b/src/test/java/ru/itmo/simplecli/executor/commands/AbstractCommandTest.java
@@ -0,0 +1,17 @@
+package ru.itmo.simplecli.executor.commands;
+
+import ru.itmo.simplecli.executor.Executable;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public abstract class AbstractCommandTest {
+
+    public void assertSuccess(Command cmd) {
+        assertEquals(Executable.EndStatus.SUCCESS, cmd.getEndStatus());
+    }
+
+    public void assertError(Command cmd) {
+        assertEquals(Executable.EndStatus.ERROR, cmd.getEndStatus());
+    }
+
+}
diff --git a/src/test/java/ru/itmo/simplecli/executor/commands/AssignmentTest.java b/src/test/java/ru/itmo/simplecli/executor/commands/AssignmentTest.java
new file mode 100644
index 0000000..0fd58d4
--- /dev/null
+++ b/src/test/java/ru/itmo/simplecli/executor/commands/AssignmentTest.java
@@ -0,0 +1,19 @@
+package ru.itmo.simplecli.executor.commands;
+
+import org.junit.jupiter.api.Test;
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class AssignmentTest extends AbstractCommandTest {
+    @Test
+    void test() {
+        var env = new EnvironmentManager();
+        var cmd = new Assignment(List.of("var", "=", "value"), env);
+        cmd.execute(null);
+        assertSuccess(cmd);
+        assertEquals("value", env.get("var"));
+    }
+}
\ No newline at end of file
diff --git a/src/test/java/ru/itmo/simplecli/executor/commands/CatTest.java b/src/test/java/ru/itmo/simplecli/executor/commands/CatTest.java
new file mode 100644
index 0000000..5ce7766
--- /dev/null
+++ b/src/test/java/ru/itmo/simplecli/executor/commands/CatTest.java
@@ -0,0 +1,53 @@
+package ru.itmo.simplecli.executor.commands;
+
+import org.junit.jupiter.api.Test;
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+abstract class CatTest extends AbstractCommandTest {
+    private final EnvironmentManager env = new EnvironmentManager();
+    private final String path = "src/test/";
+
+    @Test
+    void testFile() {
+        var cmd = new Cat(List.of(path + "testfile"), env);
+        cmd.execute(null);
+        assertSuccess(cmd);
+        assertEquals("test file", cmd.getOutput().trim());
+    }
+
+    @Test
+    void testFile2() {
+        var cmd = new Cat(List.of(path + "testfile2"), env);
+        cmd.execute(null);
+        assertSuccess(cmd);
+        assertEquals("test\nfile", cmd.getOutput().trim());
+    }
+
+    @Test
+    void testFiles() {
+        var cmd = new Cat(List.of(path + "testfile", path + "testfile"), env);
+        cmd.execute(null);
+        assertSuccess(cmd);
+        assertEquals("test file\ntest file", cmd.getOutput().trim());
+    }
+
+
+    void testNoFile() {
+        var cmd = new Cat(new ArrayList<>(), env);
+        cmd.execute("test cat");
+        assertSuccess(cmd);
+        assertEquals("test cat", cmd.getOutput().trim());
+    }
+
+    @Test
+    void testNoFileNoInput() {
+        var cmd = new Cat(new ArrayList<>(), env);
+        cmd.execute(null);
+        assertError(cmd);
+    }
+}
\ No newline at end of file
diff --git a/src/test/java/ru/itmo/simplecli/executor/commands/EchoTest.java b/src/test/java/ru/itmo/simplecli/executor/commands/EchoTest.java
new file mode 100644
index 0000000..09e4ec8
--- /dev/null
+++ b/src/test/java/ru/itmo/simplecli/executor/commands/EchoTest.java
@@ -0,0 +1,49 @@
+package ru.itmo.simplecli.executor.commands;
+
+import org.junit.jupiter.api.Test;
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class EchoTest extends AbstractCommandTest {
+
+    @Test
+    void testOneArg() {
+        var env = new EnvironmentManager();
+        var cmd = new Echo(List.of("arg"), env);
+        cmd.execute(null);
+        assertSuccess(cmd);
+        assertEquals("arg", cmd.getOutput());
+    }
+
+    @Test
+    void testMultipleArg() {
+        var env = new EnvironmentManager();
+        var cmd = new Echo(List.of("arg1", "arg2"), env);
+        cmd.execute(null);
+        assertSuccess(cmd);
+        assertEquals("arg1 arg2", cmd.getOutput());
+    }
+
+    @Test
+    void testNonemptyInput() {
+        var env = new EnvironmentManager();
+        var cmd = new Echo(List.of("arg"), env);
+        cmd.execute("something");
+        assertSuccess(cmd);
+        assertEquals("arg", cmd.getOutput());
+    }
+
+    @Test
+    void testNoArg() {
+        var env = new EnvironmentManager();
+        var cmd = new Echo(new ArrayList<>(), env);
+        cmd.execute(null);
+        assertSuccess(cmd);
+        assertEquals("", cmd.getOutput());
+    }
+
+}
\ No newline at end of file
diff --git a/src/test/java/ru/itmo/simplecli/executor/commands/ExitTest.java b/src/test/java/ru/itmo/simplecli/executor/commands/ExitTest.java
new file mode 100644
index 0000000..1705380
--- /dev/null
+++ b/src/test/java/ru/itmo/simplecli/executor/commands/ExitTest.java
@@ -0,0 +1,23 @@
+package ru.itmo.simplecli.executor.commands;
+
+import org.junit.jupiter.api.Test;
+import ru.itmo.simplecli.executor.EnvironmentManager;
+import ru.itmo.simplecli.executor.Executable;
+
+import java.util.ArrayList;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+public class ExitTest extends AbstractCommandTest {
+
+    @Test
+    void test() {
+        var env = new EnvironmentManager();
+        var cmd = new Exit(new ArrayList<>(), env);
+        cmd.execute(null);
+        assertEquals(Executable.EndStatus.EXIT, cmd.getEndStatus());
+        assertNull(cmd.getOutput());
+    }
+
+}
\ No newline at end of file
diff --git a/src/test/java/ru/itmo/simplecli/executor/commands/PwdTest.java b/src/test/java/ru/itmo/simplecli/executor/commands/PwdTest.java
new file mode 100644
index 0000000..216827b
--- /dev/null
+++ b/src/test/java/ru/itmo/simplecli/executor/commands/PwdTest.java
@@ -0,0 +1,22 @@
+package ru.itmo.simplecli.executor.commands;
+
+import org.junit.jupiter.api.Test;
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.nio.file.Paths;
+import java.util.ArrayList;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class PwdTest extends AbstractCommandTest {
+
+    @Test
+    void test() {
+        var env = new EnvironmentManager();
+        var cmd = new Pwd(new ArrayList<>(), env);
+        cmd.execute(null);
+        assertSuccess(cmd);
+        assertEquals(Paths.get("").toAbsolutePath().toString(), cmd.getOutput());
+    }
+
+}
\ No newline at end of file
diff --git a/src/test/java/ru/itmo/simplecli/executor/commands/WCTest.java b/src/test/java/ru/itmo/simplecli/executor/commands/WCTest.java
new file mode 100644
index 0000000..8650ac2
--- /dev/null
+++ b/src/test/java/ru/itmo/simplecli/executor/commands/WCTest.java
@@ -0,0 +1,79 @@
+package ru.itmo.simplecli.executor.commands;
+
+import org.junit.jupiter.api.Test;
+import ru.itmo.simplecli.executor.EnvironmentManager;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class WCTest extends AbstractCommandTest {
+    private final EnvironmentManager env = new EnvironmentManager();
+    private final String path = "src/test/";
+
+    private void assertSpaceInsensitive(String expected, String actual) {
+        var value1 = expected.trim().split("\\s+");
+        var value2 = actual.trim().split("\\s+");
+        assertArrayEquals(value1, value2);
+    }
+
+    private String callExternal(List<String> args) throws IOException, InterruptedException {
+        var process = new ProcessBuilder(args).start();
+        process.waitFor();
+        return new String(process.getInputStream().readAllBytes());
+    }
+
+    private String callExternal(List<String> args, String input) throws IOException, InterruptedException {
+        var process = new ProcessBuilder(args).start();
+        process.getOutputStream().write(input.getBytes());
+        process.getOutputStream().close();
+        return new String(process.getInputStream().readAllBytes());
+    }
+
+    @Test
+    void testFile() {
+        var filename = path + "testfile";
+        var cmd = new WC(List.of(filename), env);
+        cmd.execute(null);
+        assertSuccess(cmd);
+        try {
+            assertSpaceInsensitive(callExternal(List.of("wc", filename)), cmd.getOutput());
+        } catch (IOException | InterruptedException e) {
+            fail();
+        }
+    }
+
+    @Test
+    void testFiles() {
+        var filename = path + "testfile";
+        var cmd = new WC(List.of(filename, filename), env);
+        cmd.execute(null);
+        assertSuccess(cmd);
+        try {
+            assertSpaceInsensitive(callExternal(List.of("wc", filename, filename)), cmd.getOutput());
+        } catch (IOException | InterruptedException e) {
+            fail();
+        }
+    }
+
+    @Test
+    void testNoFile() {
+        var cmd = new WC(new ArrayList<>(), env);
+        var input = "test wc";
+        cmd.execute(input);
+        try {
+            assertSpaceInsensitive(callExternal(List.of("wc", "-"), input), cmd.getOutput() + "-");
+        } catch (IOException | InterruptedException e) {
+            fail();
+        }
+    }
+
+    @Test
+    void testNoFileNoInput() {
+        var cmd = new WC(List.of(), env);
+        cmd.execute(null);
+        assertError(cmd);
+    }
+}
diff --git a/src/test/testfile b/src/test/testfile
new file mode 100644
index 0000000..16b14f5
--- /dev/null
+++ b/src/test/testfile
@@ -0,0 +1 @@
+test file
diff --git a/src/test/testfile2 b/src/test/testfile2
new file mode 100644
index 0000000..cd0ece9
--- /dev/null
+++ b/src/test/testfile2
@@ -0,0 +1,2 @@
+test
+file