Results for “command substitution”
Small, practical examples. Search by task or narrow things down below.
Start an existing container and attach to its output
Docker / Compose: create records the command; start with attach runs that existing container.
Docker / Compose✓ Tested
Stop a running container gracefully
Docker / Compose: stop sends the configured stop signal and waits before forcing termination.
Docker / Compose✓ Tested
Supply a default for an unset Compose variable
Docker / Compose: The default interpolation form supplies a value when the variable is absent or empty.
Docker / Compose✓ Tested
Supply a non-secret configuration file
Docker / Compose: A Compose config mounts a declared file into the service.
Docker / Compose✓ Tested
Supply an environment variable to an exec process
Docker / Compose: An exec environment override applies to the new process only.
Docker / Compose✓ Tested
Use a build argument while creating an image
Docker / Compose: ARG supplies a build-time value that is not automatically a runtime environment variable.
Docker / Compose✓ Tested
Validate the number of positional arguments
Bash Scripts: Use the argument count to enforce a simple command-line contract.
Bash Scripts✓ Tested
Verify a read-only volume rejects writes
Docker / Compose: A failed write confirms the mount’s read-only behavior.
Docker / Compose✓ Tested
Verify that a one-off container was removed
Docker / Compose: An automatically removed container no longer appears in an exact-name listing.
Docker / Compose✓ Tested
Wait for a container to exit
Docker / Compose: wait blocks until the container stops and prints its exit code.
Docker / Compose✓ Tested
Wait for an actual container health check
Docker / Compose: Health reports readiness independently from process startup.
Docker / Compose✓ Tested
Wait for an initialization job
Start a service only after its dependency completes successfully.
Compose✓ Tested