Docker Shell

NAME

dosh - run a user shell in a container with cwd bind mounted

DESCRIPTION

dosh(1) is an sh-compatible frontend for docker that runs commands in a new container; using the current user, with cwd bind mounted.

Commands are read either from the standard input or from a file or from command line using one of the standard shell invocations (i.e. thanks to options -c, -i, -s or without arguments).

DOWNLOAD

Fetch your own copy and give it a try right now!

Version	Checksum (*)
6	915e275ca1314789a895504df4e149f0335b8749e2740da99009f71caaa46a38

*: Note that hashes are subject to change as GitHub might update tarball generation.

DOCUMENTATION

Build the documentation using make(1)

$ make doc
asciidoctor -b manpage -o dosh.1 dosh.1.adoc
gzip -c dosh.1 >dosh.1.gz
rm dosh.1

INSTALL

Run the following command to install dosh(1)

To your home directory

$ make user-install

Or, to your system

$ sudo make install

Traditional variables DESTDIR and PREFIX can be overridden

$ sudo make install PREFIX=/opt/dosh

Or

$ make install DESTDIR=$PWD/pkg PREFIX=/usr

TUNING

DEFAULT SHELL INTERPRETER

dosh(1) uses /bin/sh as default interpreter as it is the only reliable Shell available. The default interpreter can be set by option --shell SHELL; but it needs to be set to every call to dosh.

dosh --shell /bin/bash

Instead, the default interpreter can be set using the DOSHELL environment variable. When this variable is exported, there is no need to override the Shell interpreter through the command-line.

Adding these two following lines to the Shell ~/.profile tells dosh to uses /bin/bash as Shell interpreter.

DOSHELL="/bin/bash"
export DOSHELL

MANAGE DOSH AS A NON-ROOT USER

dosh(1) relies on the setup of Docker. See its documentation to run Docker as non-root-user.

It is not recommended to run dosh(1) using sudo in case the user does not have permission to send the context to the Docker daemon. Instead, consider setting the DOSH_DOCKER environment to sudo docker as it will only run the docker commands with the superuser privileges.

On Linux, if you are not a member of the docker group, please consider to run dosh as below:

DOSH_DOCKER="sudo docker" dosh

The DOSH_DOCKER environment can be set to the Shell profile files to make it persistent for the session.

DOCKER EXTRA OPTIONS

Every single docker(1) command performed in dosh(1) can be customized by passing extra arguments thanks its corresponding DOSH_DOCKER_xxx_EXTRA_OPTS environment variable. xxx represents one of the docker commands used in dosh (build, rmi, run, exec, attach, kill and rm).

Note: Only DOSH_DOCKER_RUN_EXTRA_OPTS is relevant for interactive usage.

As an example, consider mapping extra personal dot-files to feel at home in the container.

Adding these two following lines to the Shell ~/.profile automatically binds the ~/.ssh directory to the container.

DOSH_DOCKER_RUN_EXTRA_OPTS="--volume $HOME/.ssh:$HOME/.ssh"
export DOSH_DOCKER_RUN_EXTRA_OPTS

SHELL PROFILE EXAMPLES

Here are some examples of code to copy/paste in the ~/.profile.

They significantly improve the dosh experience.

REUSE SAME SHELL INTERPRETER

This asks dosh to use the same Shell interpreter as the one which is currently in use.

# Not sh?
if [ "$SHELL" != "/bin/sh" ]
then
	export DOSHELL="$SHELL"
fi

Important: Be aware that when the Shell interpreter is not installed in the container, dosh ends with the following error:

docker: Error response from daemon: oci runtime error: container_linux.go:265: starting container process caused "exec: \"/bin/zsh\": stat /bin/zsh: no such file or directory".

EXPORT ENVIRONMENT

These following lines export some useful environment variables to the container.

# Export some environment variables
for env in TERM EDITOR
do
	[ -n "$env" ] || continue
	DOSH_DOCKER_RUN_EXTRA_OPTS+=" --env $env"
done

MAP DOT-FILES

These following lines map some useful dot-files to the container.

# Map some home dot-files
for vol in $HOME/.config $HOME/.local $HOME/.profile
do
	[ -e "$vol" ] || continue
	DOSH_DOCKER_RUN_EXTRA_OPTS+=" --volume $vol:$vol"
done

# Map extra home dot-files
for vol in $HOME/.inputrc $HOME/.gnupg $HOME/.screenrc
do
	[ -e "$vol" ] || continue
	DOSH_DOCKER_RUN_EXTRA_OPTS+=" --volume $vol:$vol"
done

bash(1) invocation files is a must-have to feel like home.

# Map bash dot-files
for vol in $HOME/.bash{_profile,rc,login,logout}
do
	[ -e "$vol" ] || continue
	DOSH_DOCKER_RUN_EXTRA_OPTS+=" --volume $vol:$vol"
done

zsh(1) too.

# Map zsh dot-files
zdotdir="${ZDOTDIR:-$HOME}"
for vol in $zdotdir/.zshenv $zdotdir/.zprofile $zdotdir/.zshrc $HOME/.zlogin $HOME/.zlogout
do
	[ -e "$vol" ] || continue
	DOSH_DOCKER_RUN_EXTRA_OPTS+=" --volume $vol:$vol"
done

SSH HANDLING

For a better experience with SSH, these following lines should be considered.

# Map and export ssh things?
if [ -d "$HOME/.ssh" ]
then
	DOSH_DOCKER_RUN_EXTRA_OPTS+=" --volume $HOME/.ssh:$HOME/.ssh"
fi
if [ -n "$SSH_AUTH_SOCK" ]
then
	DOSH_DOCKER_RUN_EXTRA_OPTS+=" --env SSH_AUTH_SOCK"
	DOSH_DOCKER_RUN_EXTRA_OPTS+=" --volume $SSH_AUTH_SOCK:$SSH_AUTH_SOCK"
fi

X

To enable X in docker, these following lines should be considered.

# Map and export X things?
if [ -n "$DISPLAY" ]
then
	for env in DISPLAY XAUTHORITY XSOCK
	do
		[ -n "$env" ] || continue
		DOSH_DOCKER_RUN_EXTRA_OPTS+=" --env $env"
	done
	dotxauthority="${XAUTHORITY:-$HOME/.Xauthority}"
	if [ -e "$dotxauthority" ]
	then
		DOSH_DOCKER_RUN_EXTRA_OPTS+=" --volume $dotxauthority:$HOME/.Xauthority"
	fi
	unset dotxauthority
	xsock="${XSOCK:-/tmp/.X11-unix}"
	if [ -e "$xsock" ]
	then
		DOSH_DOCKER_RUN_EXTRA_OPTS+=" --volume $xsock:/tmp/.X11-unix:ro"
	fi
	unset xsock
fi

Note: To enable X through SSH, please have a look to the excellent post of Jean-Tiare Le Bigot on its blog yadutaf.

MAKE THE PROMPT SLIGHTLY DIFFERENT

Colorize the prompt from the container in a different way to distinguish dosh sessions.

# In dosh?
if [ -z "$DOSHLVL" ]
then
	return
fi

# Colorize prompt color differently
PS1="${PS1//32/33}"
PROMPT="${PROMPT//blue/green}"

Note: Put these lines to the end of the file.

Lines after the if statement are applied in the container.

LINKS

Check for man-pages and its examples.

Also, here is an extra example that builds the documentation

$ echo FROM ubuntu >Dockerfile
$ echo RUN apt-get update && apt-get install -y asciidoctor >>Dockerfile

$ cat Dockerfile
FROM ubuntu
RUN apt-get update && apt-get install -y asciidoctor

$ dosh -c asciidoctor -b manpage -o - dosh.1.adoc | gzip -c - >dosh.1.gz
sha256:ced062433e33

$ man ./dosh.1.gz

Enjoy!

BUGS

Report bugs at https://github.com/gportay/dosh/issues

AUTHOR

Written by Gaël PORTAY gael.portay@gmail.com

COPYRIGHT

Copyright (c) 2017-2020,2023-2024 Gaël PORTAY

This program is free software: you can redistribute it and/or modify it under the terms of the MIT License.