private void initializeEnvironment() {
    env.put(ENV_SYS_USER, System.getProperty("user.name"));
    env.put(ENV_SYS_USER_HOME, System.getProperty("user.home"));
    env.put(ENV_SYS_HOST_NAME, new HostName().determineHostName());
    env.put(ENV_SYS_CLASSPATH, System.getProperty("java.class.path"));
    env.put(ENV_SYS_JAVA_VERSION, System.getProperty("java.version"));
    env.put(ENV_SYS_OS, System.getProperty("os.name"));
    env.put(ENV_SYS_OS_LINE_SEPARATOR, lineSeparator());
    env.put(ENV_SYS_GEODE_HOME_DIR, System.getenv("GEODE_HOME"));

    env.put(ENV_APP_NAME, Gfsh.GFSH_APP_NAME);
    readonlyAppEnv.add(ENV_APP_NAME);
    env.put(ENV_APP_LOGGING_ENABLED,
        String.valueOf(!Level.OFF.equals(gfshConfig.getLogLevel())));
    readonlyAppEnv.add(ENV_APP_LOGGING_ENABLED);
    env.put(ENV_APP_LOG_FILE, gfshConfig.getLogFilePath());
    readonlyAppEnv.add(ENV_APP_LOG_FILE);
    env.put(ENV_APP_PWD, System.getProperty("user.dir"));
    readonlyAppEnv.add(ENV_APP_PWD);
    env.put(ENV_APP_FETCH_SIZE, String.valueOf(DEFAULT_APP_FETCH_SIZE));
    env.put(ENV_APP_LAST_EXIT_STATUS, String.valueOf(DEFAULT_APP_LAST_EXIT_STATUS));
    readonlyAppEnv.add(ENV_APP_LAST_EXIT_STATUS);
    env.put(ENV_APP_COLLECTION_LIMIT, String.valueOf(DEFAULT_APP_COLLECTION_LIMIT));
    env.put(ENV_APP_QUERY_RESULTS_DISPLAY_MODE, DEFAULT_APP_QUERY_RESULTS_DISPLAY_MODE);
    env.put(ENV_APP_QUIET_EXECUTION, String.valueOf(DEFAULT_APP_QUIET_EXECUTION));
    env.put(ENV_APP_RESULT_VIEWER, DEFAULT_APP_RESULT_VIEWER);
  }
Initializes default environment variables to default values
geode-gfsh/src/main/java/org/apache/geode/management/internal/cli/shell/Gfsh.java