🐳 Day 4: Mastering docker ps Command - With examlpe’s!

This guide provides a deep dive of the docker ps command, including how to list, filter, format, and count containers and images. Docker ps command lists containers on your system. It displays useful information such as container IDs, image names, uptime, exposed ports and many more.. It's an essential tool to working with the containers. 🐳📋

🎬 Video Demonstration

📋 Basic Usage

❔ Get Help using help command

docker ps --help

Usage:  docker ps [OPTIONS]

List containers

Aliases:
  docker container ls, docker container list, docker container ps, docker ps

Options:
  -a, --all             Show all containers (default shows just running)
  -f, --filter filter   Filter output based on conditions provided
      --format string   Format output using a custom template:
                        'table':            Print output in table format with column headers (default)
                        'table TEMPLATE':   Print output in table format using the given Go template
                        'json':             Print in JSON format
                        'TEMPLATE':         Print output using the given Go template.
                        Refer to https://docs.docker.com/go/formatting/ for more information about formatting output with templates
  -n, --last int        Show n last created containers (includes all states) (default -1)
  -l, --latest          Show the latest created container (includes all states)
      --no-trunc        Don't truncate output
  -q, --quiet           Only display container IDs
  -s, --size            Display total file sizes

1. Show Running Containers

docker ps

2. Show All Containers (Running + Stopped)

docker ps -a

3. Show Disk Usage per Container

docker ps -s
docker ps -as

4. Show Last N Created Containers

docker ps --last 4
# or
docker ps -n 4

5. Show the Most Recently Created Container

docker ps -l
# or
docker ps --latest

6. Show Only container IDs

docker ps -q
docker ps -aq
# or
docker ps --quiet
docker ps -a --quiet

---

🔍 Filtering Containers

Filter by Name

docker ps -f "name=test-container"
or
docker ps --filter "name=test-container"

Filter by Container ID

docker ps -a -f "id=aca09d8707d8"
or
docker ps -a --filter "id=aca09d8707d8"

Filter by Status

docker ps --filter status=running
docker ps --filter status=exited

Filter by Ancestor (Image)

docker ps --filter ancestor=nginx

Filter by Creation Time before/after container

docker ps -f before=whoami
docker ps -f since=nd

Sort containers by creation time (most recent first)

docker ps -a --format '{{.CreatedAt}}\t{{.Names}}' | sort -r

Filter by Network, Volume, Port, Label, Health

docker ps --filter publish=8080
docker ps --filter "label=com.example.app=web"
docker ps --filter health=healthy
docker ps --filter network=bridge
docker ps --filter volume=myvol
docker ps -a --filter exited=0

Multiple Filters

docker ps --filter status=running --filter ancestor=nginx

🔢 Counting Containers

Count Running Containers

docker ps -q | wc -l

Get Count via Docker Info

docker info --format '{{json .ContainersRunning}}'

Count All Containers (Running + Stopped)

docker ps -a -q | wc -l

Count Matching Containers by Image Name

docker ps | grep ibraransaridocker/coming-soon | wc -l

🛠️ Custom Formatting

Simple Name Format

docker ps --format '{{.Names}}'
or
docker ps -a --format "{{.Names}}"
or
docker ps -a --format "table {{.Names}}"

Detailed Format with Variables

FORMAT="\nID\t{{.ID}}\nIMAGE\t{{.Image}}\nCOMMAND\t{{.Command}}\nCREATED\t{{.RunningFor}}\nSTATUS\t{{.Status}}\nPORTS\t{{.Ports}}\nNAMES\t{{.Names}}\n"
docker ps -a --format="$FORMAT"

Tabular Format Output

docker ps -a --format "table {{.Names}}\t{{.ID}}\t{{.Status}}\t{{.Ports}}\t{{.Image}}\t{{.Command}}\t{{.RunningFor}}"

---

🔍 Inspect Available Format Fields

View Raw Output in JSON

docker ps --format '{{json .}}' | jq

List All Available Format Keys

docker ps --format '{{json .}}' | jq -r 'keys_unsorted[]' | sort -u

List All Format Keys from All Containers

# Create sample container to provide all keys
docker run -itd \
  --name test-container \
  --hostname custom-hostname \
  --env MY_ENV=example \
  --label app=demo \
  --label com.example.app=web \
  --mount type=bind,source=/tmp,target=/app/tmp,readonly \
  --mount type=volume,source=myvol,target=/app/data \
  --network bridge \
  --publish 8080:80 \
  --restart unless-stopped \
  --memory 512m \
  --cpu-shares 512 \
  --health-cmd="curl -f http://localhost || exit 1" \
  --health-interval=30s \
  --health-retries=3 \
  --health-start-period=5s \
  nginx:latest

# Run to get key
docker inspect $(docker ps -q) | jq '.[0] | keys_unsorted' | sort -u
# or
docker inspect $(docker ps -q) | jq -r '.[0] | keys_unsorted[]' | sort -u

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🧩 All Available --format Fields

Here are all the fields you can use with --format:

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📚 More Info

For full details, check the official Docker formatting docs 📘

Happy Dockering! 🐳✨