Listing containers (docker ps, docker ps -a) - Step-by-Step Execution

Process Flow - Listing containers (docker ps, docker ps -a)

Start

↓

Run 'docker ps'

↓

Show running containers

↓

Run 'docker ps -a'

↓

Show all containers (running + stopped)

↓

End

The flow shows running 'docker ps' to list running containers, then 'docker ps -a' to list all containers including stopped ones.

Execution Sample

Docker

docker ps

docker ps -a

Lists running containers first, then lists all containers including stopped ones.

Process Table

Step	Command	Action	Output Example	Notes
1	docker ps	List running containers only	CONTAINER ID IMAGE STATUS NAMES abc123 nginx Up 2 hours webserver	Shows only containers currently running
2	docker ps -a	List all containers (running + stopped)	CONTAINER ID IMAGE STATUS NAMES abc123 nginx Up 2 hours webserver def456 redis Exited (0) 3 hours redisdb	Shows all containers including stopped ones

💡 Commands complete after listing containers; no further action.

Status Tracker

Variable	Start	After 'docker ps'	After 'docker ps -a'
Running Containers List	[]	[{ID: 'abc123', Image: 'nginx', Status: 'Up 2 hours', Name: 'webserver'}]	[{ID: 'abc123', Image: 'nginx', Status: 'Up 2 hours', Name: 'webserver'}]
All Containers List	[]	[]	[{ID: 'abc123', Image: 'nginx', Status: 'Up 2 hours', Name: 'webserver'}, {ID: 'def456', Image: 'redis', Status: 'Exited (0) 3 hours', Name: 'redisdb'}]

Key Moments - 2 Insights

Why does 'docker ps' show fewer containers than 'docker ps -a'?

'docker ps' shows only running containers (see execution_table step 1), while 'docker ps -a' shows all containers including stopped ones (step 2).

What does the 'Exited' status mean in 'docker ps -a' output?

'Exited' means the container has stopped running but still exists on the system, visible only with 'docker ps -a' (execution_table step 2).

Visual Quiz - 3 Questions

Look at the execution table, what does 'docker ps' list at step 1?

A Only running containers

B Only stopped containers

C All containers including stopped ones

D No containers at all

💡 Hint

Check the 'Output Example' column in execution_table row for step 1.

At which step does the command show containers with status 'Exited'?

A Step 1

B Both steps

C Step 2

D Neither step

💡 Hint

Look at the 'Output Example' column for 'Exited' status in execution_table.

If a container is stopped, which command will show it?

A docker ps

B docker ps -a

C docker start

D docker run

💡 Hint

Refer to variable_tracker showing 'All Containers List' after 'docker ps -a'.

Concept Snapshot

docker ps: Lists only running containers.
docker ps -a: Lists all containers including stopped ones.
Use 'docker ps' to see active containers.
Use 'docker ps -a' to see full container history.
'Exited' status means container is stopped but exists.
These commands help manage container states quickly.

Full Transcript

This visual execution shows how 'docker ps' lists only running containers, while 'docker ps -a' lists all containers including stopped ones. Step 1 runs 'docker ps' and outputs running containers. Step 2 runs 'docker ps -a' and outputs all containers with their statuses. Variables track container lists after each command. Key moments clarify why outputs differ and what 'Exited' means. The quiz tests understanding of these differences and command outputs.