Apt-add-itory: 命令在 Dockerfile 没有发现错误

我只是在我的终端里做了一个非常简单的 Docker 文件，基本上我做了以下几件事:

mkdir pgrouted
cd pgrouted
touch Dockerfile

现在，我在 纳米机器人编辑器中打开 Docker 文件，并向 Docker 文件添加以下命令:

FROM ubuntu


MAINTAINER Gautam <gautamx07@yahoo.com>


LABEL Description="pgrouting excercise" Vendor="skanatek" Version="1.0"


ENV BBOX="-122.8,45.4,-122.5,45.6"


# Add pgRouting launchpad repository
RUN sudo apt-add-repository -y ppa:ubuntugis/ppa
RUN sudo apt-add-repository -y ppa:georepublic/pgrouting
RUN sudo apt-get update


# Install pgRouting package (for Ubuntu 14.04)
RUN sudo apt-get install postgresql-9.3-pgrouting


# Install osm2pgrouting package
RUN sudo apt-get install osm2pgrouting


# Install workshop material (optional, but maybe slightly outdated)
RUN sudo apt-get install pgrouting-workshop


# For workshops at conferences and events:
# Download and install from http://trac.osgeo.org/osgeo/wiki/Live_GIS_Workshop_Install
RUN wget --no-check-certificate https://launchpad.net/~georepublic/+archive/pgrouting/+files/pgrouting-workshop_2.0.6-ppa1_all.deb


RUN sudo dpkg -i pgrouting-workshop_2.0.6-ppa1_all.deb


# Review: Not sure weather this should be in the dockerfile
RUN cp -R /usr/share/pgrouting/workshop ~/Desktop/pgrouting-workshop


# Log in as user "user"
RUN psql -U postgres


# Create routing database
RUN CREATE DATABASE routing;


# Add PostGIS functions
RUN CREATE EXTENSION postgis;


# Add pgRouting core functions
CREATE EXTENSION pgrouting;


# Download using Overpass XAPI (larger extracts possible than with default OSM API)
wget --progress=dot:mega -O "sampledata.osm" "http://www.overpass-api.de/api/xapi?*[bbox=${BBOX}][@meta]"

整个 Dockerfile 可以一目了然地看到 翻译: 奇芳。

现在，当我尝试构建 Dockerfile 时，像这样:

docker build -t gautam/pgrouted:v1 .

运行 Dockerfile，然后我得到下面的错误:

Step 4 : RUN sudo apt-add-repository -y ppa:ubuntugis/ppa
---> Running in c93c3c5fd5e8
sudo: apt-add-repository: command not found
The command '/bin/sh -c sudo apt-add-repository -y ppa:ubuntugis/ppa' returned a non-zero code: 1

为什么我会得到这个错误？