Once you’ve shelled into a Docker container using docker exec or docker attach, you might want to view or edit a file inside the container—for example, to change a config setting, debug an issue, or test a script in real time.
But since containers are often minimal and might not have text editors installed, you’ll need to know the right tools and commands to edit files effectively.
In this blog post, we’ll show you how to edit a file inside a running Docker container using different methods.
🧭 Step 1: Shell into the Container
Use the following command to open a shell session inside your running container:
docker exec -it <container_name_or_id> /bin/sh
Or, if the container has Bash:
docker exec -it <container_name_or_id> /bin/bash
Tip: You can find the container name with
docker ps.
✏️ Step 2: Try a Built-In Text Editor
Option A: Use vi or vim (if available)
vi /path/to/file
But many lightweight images (like Alpine or BusyBox) don’t include vi/vim by default.
Option B: Use nano (if available)
nano /path/to/file
If you get a “command not found” error, you’ll need to install an editor.
🧰 Step 3: Install a Text Editor in the Container (Temporary)
To install an editor like vi or nano, you’ll need a package manager—if the container has one.
Debian/Ubuntu-based container:
apt update && apt install nano -y
Alpine-based container:
apk add nano
Now you can open files with:
nano /path/to/file
Note: Any changes you make inside a container are temporary unless you commit them or mount volumes.
🛑 Step 4: Alternative Method — Copy the File to Host, Edit, and Re-copy
If installing an editor isn’t an option, do the editing on your host machine:
Copy file from container to host:
docker cp <container_id>:/path/in/container/file.txt ./file.txt
Edit the file locally using any editor.
Then copy it back into the container:
docker cp ./file.txt <container_id>:/path/in/container/file.txt
💾 Step 5: Make Your Edits Persistent
Containers are ephemeral—changes are lost once the container is restarted unless:
- You’re editing a mounted volume, or
- You commit the container to create a new image:
docker commit <container_id> edited-container
Then run containers from that new image.
📝 Conclusion
Editing a file inside a Docker container is easy if you know the tools available. While some containers include vi or nano, many don’t—so you may need to install them or use docker cp to edit locally.
🔑 Summary
| Method | When to Use |
|---|---|
vi or nano | If available inside container |
apt install nano | If using a Debian/Ubuntu-based image |
docker cp | If editor is unavailable or limited |
| Commit or mount volume | To make changes persistent |