CODEWITHSUNDEEP
dockercommand-line-interfaceeditor
Igor Barinov
Igor Barinov

Reputation: 25530

How do I edit a file after I shell to a Docker container?

I successfully shelled to a Docker container using:

docker exec -i -t 69f1711a205e bash

Now I need to edit file and I don't have any editors inside:

root@69f1711a205e:/# nano
bash: nano: command not found
root@69f1711a205e:/# pico
bash: pico: command not found
root@69f1711a205e:/# vi
bash: vi: command not found
root@69f1711a205e:/# vim
bash: vim: command not found
root@69f1711a205e:/# emacs
bash: emacs: command not found
root@69f1711a205e:/#

How do I edit files?

Upvotes: 864

Views: 889578

Answers (27)

Susobhan Das
Susobhan Das

Reputation: 1144

Working Solution #simplified

Need to install as root user, to update the linux as well as install application.

  1. docker bash as root user
docker exec -u 0 -it app22-jenkins-1 bash
  1. Update linux
apt update -y
  1. Upgrade
apt upgrade -y
  1. install vim
apt install vim -y

Upvotes: 1

Mac
Mac

Reputation: 357

First copy the file out of the container:

docker cp my-container:/data/scripts/main.py main.py

Then edit locally with your vi, emacs or whatever, then put it back:

docker cp main.py my-container:/data/scripts/main.py

Upvotes: 3

Douglas Krugman
Douglas Krugman

Reputation: 164

If you are using Docker Desktop, you can click on the container, view the files from the files tab, and right-click on any file to edit it!

Upvotes: 3

ziff
ziff

Reputation: 369

If you are looking for small, try nano-tiny!

apt-get update
apt-get install nano-tiny

FWIW, the Postgres Docker Image was built with linuxkit.

For info and to compare... My Container reports:

# apt-cache show nano-tiny
Package: nano-tiny
Source: nano
Version: 7.2-1
Installed-Size: 187
Maintainer: Jordi Mallach <[email protected]>

# apt-cache show vim-tiny
Package: vim-tiny
Source: vim
Version: 2:9.0.1378-2
Installed-Size: 1689
Maintainer: Debian Vim Maintainers <[email protected]>

If you do not need VI editor features then maybe this version of nano is just right for you.

I hope this helps!

Upvotes: 2

aas4mis
aas4mis

Reputation: 93

I used a mysql:8.0 container and found there was no text editor installed. There was also no package manager installed??? Luckily I had VS Code installed with the docker extension. With the docker extension you can view all running (and closed) containers and drill down into the file system, just as if it were a local file system.

HTH!

enter image description here

Upvotes: 3

Jignesh Nakrani
Jignesh Nakrani

Reputation: 9

You can view the file content in running container without installing anything

Method 1: if you are using vs code, then install a docker extension. Then when you run the container, click on docker icon on left side bar. It shows the directory structure of running container. you can drill down to your directory from gui, and open the file content.

Method 2: if you want to do it by command line, from powershell, run the command

docker exec -it containerid sh

then go to your directory using cd where your file is.

then use the command "more --lines 10 index.html" (or your file name)

this will allow to view 10 lines at a time. pressing enter will display next 10 lines

Upvotes: 0

Abderrahim Oujbih
Abderrahim Oujbih

Reputation: 60

You can install nano

yum install nano

Upvotes: 3

Dibya Darshan Khanal
Dibya Darshan Khanal

Reputation: 65

Make sure to update the container before trying to install the editor.

apt-get update
apt-get install nano vi

Upvotes: 1

Siwei
Siwei

Reputation: 21549

docker comes up with no editors. so simply install vim, 36MB space don't kill your docker!

Upvotes: -2

salah
salah

Reputation: 21

First login as root : docker run -u root -ti bash Type following commands: apt-get update && apt-get install nano

Upvotes: 0

Opal
Opal

Reputation: 84756

As in the comments, there's no default editor set - strange - the $EDITOR environment variable is empty. You can log in into a container with:

docker exec -it <container> bash

And run:

apt-get update
apt-get install vim

Or use the following Dockerfile:

FROM  confluent/postgres-bw:0.1

RUN ["apt-get", "update"]
RUN ["apt-get", "install", "-y", "vim"]

Docker images are delivered trimmed to the bare minimum - so no editor is installed with the shipped container. That's why there's a need to install it manually.

EDIT

I also encourage you to read my post about the topic.

Upvotes: 1096

etemtezcan
etemtezcan

Reputation: 51

If you can only shell into container with bin/sh (in case bin/bash doesn't work) and apt or apt-get doesn't work in the container, check whether apk is installed by entering apk in command prompt inside the container. If yes, you can install nano as follows: apk add nano

then nano will work as usual

Upvotes: 5

aptlt
aptlt

Reputation: 503

You can use cat if installed, with the > caracter. Here is the manipulation :

cat > file_to_edit
#1 Write or Paste you text
#2 don't forget to leave a blank line at the end of file
#3 Ctrl + C to apply configuration

Now you can see the result with the command

cat file

Upvotes: 34

xD3ath
xD3ath

Reputation: 389

You can open existing file with 

cat filename.extension

and copy all the existing text on clipboard.

Then delete old file with 

rm filename.extension

or rename old file with 

mv old-filename.extension new-filename.extension

Create new file with 

cat > new-file.extension

Then paste all text copied on clipboard, press Enter and exit with save by pressing ctrl+z. And voila no need to install any kind of editors.

Upvotes: 29

simhumileco
simhumileco

Reputation: 34515

For common edit operations I prefer to install vi (vim-tiny), which uses only 1491 kB or nano which uses 1707 kB.

In other hand vim uses 28.9 MB.

We have to remember that in order for apt-get install to work, we have to do the update the first time, so:

apt-get update
apt-get install vim-tiny

To start the editor in CLI we need to enter vi.

Upvotes: 24

meijsermans
meijsermans

Reputation: 2151

You can use cat if it's installed, which will most likely be the case if it's not a bare/raw container. It works in a pinch, and ok when copy+pasting to a proper editor locally.

cat > file
# 1. type in your content
# 2. leave a newline at end of file
# 3. ctrl-c / (better: ctrl-d)
cat file

cat will output each line on receiving a newline. Make sure to add a newline for that last line. ctrl-c sends a SIGINT for cat to exit gracefully. From the comments you see that you can also hit ctrl-d to denote end-of-file ("no more input coming").

Another option is something like infilter which injects a process into the container namespace with some ptrace magic: https://github.com/yadutaf/infilter

Upvotes: 190

Aidar Gatin
Aidar Gatin

Reputation: 843

If you use Windows container and you want change any file, you can get and use Vim in Powershell console easily.

To shelled to the Windows Docker container with PowerShell:

docker exec -it <name> powershell

  • First install Chocolatey package manager

    Invoke-WebRequest https://chocolatey.org/install.ps1 -UseBasicParsing | Invoke-Expression;

  • Install Vim

    choco install vim

  • Refresh ENVIRONMENTAL VARIABLE You can just exit and shell back to the container

  • Go to file location and Vim it vim file.txt

Upvotes: 5

Shihe Zhang
Shihe Zhang

Reputation: 2771

See Stack Overflow question sed edit file in place

It would be a good option here, if:

  1. To modify a large file, it's impossible to use cat.

  2. Install Vim is not allowed or takes too long. My situation is using the MySQL 5.7 image when I want to change the my.cnf file, there is no vim, vi, and Vim install takes too long (China Great Firewall). sed is provided in the image, and it's quite simple. My usage is like

    sed -i /s/testtobechanged/textwanted/g filename

    Use man sed or look for other tutorials for more complex usage.

Upvotes: 7

David Dehghan
David Dehghan

Reputation: 24775

You can just edit your file on host and quickly copy it into and run it inside the container. Here is my one-line shortcut to copy and run a Python file:

docker cp main.py my-container:/data/scripts/ ; docker exec -it my-container python /data/scripts/main.py

Upvotes: 10

Dos
Dos

Reputation: 2507

After you shelled to the Docker container, just type:

apt-get update
apt-get install nano

Upvotes: 9

Saubhagya Srivastava
Saubhagya Srivastava

Reputation: 174

An easy way to edit a few lines would be:

echo "deb http://deb.debian.org/debian stretch main" > sources.list

Upvotes: 1

bbeecher
bbeecher

Reputation: 6453

It is kind of screwy, but in a pinch you can use sed or awk to make small edits or remove text. Be careful with your regex targets of course and be aware that you're likely root on your container and might have to re-adjust permissions.

For example, removing a full line that contains text matching a regex:

awk '!/targetText/' file.txt > temp && mv temp file.txt

(More)

Upvotes: 4

Matthew
Matthew

Reputation: 6599

To keep your Docker images small, don't install unnecessary editors. You can edit the files over SSH from the Docker host to the container:

vim scp://remoteuser@containerip//path/to/document

Upvotes: 66

yan
yan

Reputation: 1541

Sometime you must first run the container with root:

docker exec -ti --user root <container-id> /bin/bash

Then in the container, to install Vim or something else:

apt-get install vim

Upvotes: 24

MaxiReglisse
MaxiReglisse

Reputation: 3336

You can also use a special container which will contain only the command you need: Vim. I chose python-vim. It assumes that the data you want to edit are in a data container built with the following Dockerfile:

FROM debian:jessie
ENV MY_USER_PASS my_user_pass
RUN groupadd --gid 1001 my_user
RUN useradd -ms /bin/bash --home /home/my_user \
            -p $(echo "print crypt("${MY_USER_PASS:-password}", "salt")" | perl) \
            --uid 1001 --gid 1001 my_user
ADD src /home/my_user/src
RUN chown -R my_user:my_user /home/my_user/src
RUN chmod u+x /home/my_user/src
CMD ["true"]

You will be able to edit your data by mounting a Docker volume (src_volume) which will be shared by your data container (src_data) and the python-vim container.

docker volume create --name src_volume
docker build -t src_data .
docker run -d -v src_volume:/home/my_user/src --name src_data_1 src_data
docker run --rm -it -v src_volume:/src fedeg/python-vim:latest

That way, you do not change your containers. You just use a special container for this work.

Upvotes: 0

hkong
hkong

Reputation: 9062

If you don't want to add an editor just to make a few small changes (e.g., change the Tomcat configuration), you can just use:

docker cp <container>:/path/to/file.ext .

which copies it to your local machine (to your current directory). Then edit the file locally using your favorite editor, and then do a

docker cp file.ext <container>:/path/to/file.ext

to replace the old file.

Upvotes: 758

ynux
ynux

Reputation: 1366

I use "docker run" (not "docker exec"), and I'm in a restricted zone where we cannot install an editor. But I have an editor on the Docker host.

My workaround is: Bind mount a volume from the Docker host to the container (https://docs.docker.com/engine/reference/run/#/volume-shared-filesystems), and edit the file outside the container. It looks like this:

docker run -v /outside/dir:/container/dir

This is mostly for experimenting, and later I'd change the file when building the image.

Upvotes: 10

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