hadolint
dockerfile linter that validates best practices and common mistakes
TLDR
Lint Dockerfile
$ hadolint [Dockerfile]
Lint from stdin$ cat Dockerfile | hadolint -
Ignore specific rules$ hadolint --ignore [DL3008] [Dockerfile]
Output as JSON$ hadolint --format json [Dockerfile]
Show trusted registries$ hadolint --trusted-registry [docker.io] [Dockerfile]
SYNOPSIS
hadolint [options] dockerfile
DESCRIPTION
Hadolint is a Dockerfile linter that validates best practices and common mistakes. It uses ShellCheck to validate shell commands in RUN instructions.
The tool checks for security issues, inefficient layering, and deprecated syntax. It helps create optimized, secure container images.
PARAMETERS
DOCKERFILE
Dockerfile to lint.--ignore RULE
Ignore specific rule.--format FMT
Output format (tty, json, codeclimate).--trusted-registry REG
Trusted container registry.--config FILE
Config file path.--no-color
Disable colored output.--help
Display help information.
CAVEATS
Shell checking requires bash syntax. Some rules may not apply to all use cases. Configuration file recommended.
HISTORY
Hadolint was created to improve Dockerfile quality by combining Docker best practices with ShellCheck's shell analysis.
SEE ALSO
docker(1), shellcheck(1), dockerfile(5)