Copy File To Docker Container

The short answer

The docker cp command allows you to copy files and directories from your local machine to a running container.

$ docker cp src_path container:dest_path

Where:

• src\_path is the path on your local machine of the file you want to copy.
• container is the name or the ID of the container you want to copy files to.
• dest\_path is the path in the container of the directory you want to copy files to.

To get the name or ID of the container you want to copy files to, you can use the docker ps command, which will output the list of all the running containers.

Use Warp's Workflows feature to easily recall the syntax

If you’re using Warp as your terminal and you need to quickly retrieve this command, you can use Warp's Workflows feature by pressing CTRL-SHIFT-R and typing copy files:

Then pressing ENTER to use the suggested command:

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Using docker cp to copy files to docker containers

Copying individual files

To copy a file to a container, you can either use its relative or absolute path, and specify the destination directory as follows:

$ docker cp ./file.txt container:/app/

Alternatively, you can copy and rename at the same time, by providing the full destination path:

$ docker cp ./file.txt container:/app/script.txt

Note that it is not possible to copy multiple files at once using the docker cp command, unless you either use a for loop:

for file in *.txt; do docker cp $file container:/app; done

Or copy the entire directory that contains them (if located in the same directory).

Copying entire directories recursively

When copying a directory, the docker cp command will behave like the Unix cp -a command, which means that the directory will be copied recursively with permission preserved if possible.

$ docker cp ./dir container:/app/

Copying absolute and relative paths, such as a parent directory

The docker cp assumes container paths are relative to the container's root directory (i.e. /). A destination path can therefore be written with or without the initial forward slash, as docker cp will see these two commands as identical:

$ docker cp ./file.txt container:tmp

 $ docker cp ./file.txt container:/tmp

Source paths on the other hand, can be written either in their relative form:

$ docker cp ./file.txt container:/tmp

Or in their absolute form:

$ docker cp /home/johndoe/Documents/file.txt container:/tmp

You can learn more about the docker cp command in the official Docker documentation.

Copying files at build-time using a Dockerfile

A Dockerfile is a text file that contains all the necessary instructions for building a Docker image. These instructions can be used for installing and configuring command line tools, declaring environment variables, exposing ports, copying files from the local environment, and so on.

To copy files and directory at build-time, you can use the COPY instruction:

Where:

• src is the path on your local machine of the file(s) you want to copy.
• dest is the path on the container you want to copy the file to.

COPY source path options

Unlike with the docker cp command, the COPY instruction allows you to copy multiple sources at once–which can be files, directories, or both–by separating them with a whitespace character:

COPY file.txt dir /app

These source paths may also contain wildcards:

COPY *.txt /app

It is important to note that the paths of the source files and directories will be interpreted as relative to the source of the context of the build, which means that only the files contained in the directory where the Dockerfile is located will be copied.

You can therefore copy the entire directory of the build context using the dot notation:

COPY . /app

But you cannot copy files that are outside of the build context of the Dockerfile:

# This command will not work
 COPY ../file.txt /app

Also note that when copying a directory, only the content of the directory will be copied, but not the directory itself.

For example, the following command will copy the content of the dir directory into the /app directory:

COPY dir /app

COPY destination path options

The destination path may either be an absolute path:

COPY file /app

Or a path relative to the one specified in the WORKDIR instruction:

WORKDIR /app
 COPY file .

The WORKDIR instruction is used to set the working directory for instructions such as COPY, ADD, RUN, etc. If the specified directory doesn't exist, it will be automatically created. In Unix, this is the equivalent of the following command:

$ mkdir dir && cd dir