Command line switches
Most configuration options are also available as command line switches, so that you can e.g. only run certain checks at a time to focus attention on those issues.
Common use cases
Here are a couple of common use case and their respective command line switches:
Output Formats
Use --format to format the output in one of the following formats:
Additionally, you can deactivate the output's coloring by using --no-color.
Watch & re-run analysis on file changes
Use --watch to watch for file changes and re-run the analysis.
mix credo --watch
mix credo list --only readability --watch
mix credo diff v1.4.0 --watch
Only run some checks
To run only a subset of checks, you can use the --checks or the -c alias (also aliased as --only).
# to only run the Readability checks, use:
$ mix credo --only readability
# to only run Readability checks and Warnings, use:
$ mix credo --only readability,warning
The second example illustrates how the command takes a comma-separated list. All commands matching any of the passed items will be run.
You can use partial names to quickly run checks. mix credo --only todo will show all # TODO comments since todo will match Credo.Check.Design.TagTODO. mix credo --only inspect will show you all calls to IO.inspect since it matches Credo.Check.Warning.IoInspect.
Ignore some checks
To ignore selected checks, you can use the --ignore-checks or the -i alias (also aliased as --ignore).
# to ignore all Readability checks, use:
$ mix credo --ignore readability
# to ignore all Readability checks and the DuplicatedCode check, use:
$ mix credo --ignore readability,duplicated
The second example illustrates how the command takes a comma-separated list. All commands matching any of the passed items will be ignored.
You can use partial names to quickly exclude checks. mix credo --ignore nameredec will exclude all checks for variables/parameters having the same name as declared functions by matching Credo.Check.Warning.NameRedeclarationBy...
Re-enable disabled checks
Use --enable-disabled-checks [pattern] to re-enable checks that were disabled in the config using {CheckModule, false}. This comes in handy when using checks on a case-by-case basis
As with other check-related switches, pattern is a comma-delimited list of patterns:
$ mix credo info --enable-disabled-checks Credo.Check.Readability.Specs,Credo.Check.Refactor.DoubleBooleanNegation
Of course, we can have the same effect by choosing the pattern less explicitly:
$ mix credo info --enable-disabled-checks specs,double
Parsing source from STDIN
You can also use Credo to parse source that has been piped directly into it.
This is especially useful when integrating with external editors. You can use this feature by passing the --read-from-stdin option as follows:
$ echo 'IO.puts("hello world");' | mix credo --format flycheck --read-from-stdin
# stdin:1: C: There is no whitespace around parentheses/brackets most of the time, but here there is.
Notice the origin if the source is coming annotated as stdin, you can change this annotation by passing it along after option like so:
$ echo 'IO.puts("hello world");' | mix credo --format flycheck --read-from-stdin /path/representing/the_current/source.ex
# /path/representing/the_current/source.ex:1: C: There is no whitespace around parentheses/brackets most of the time, but here there is.
Do note with the passed option as filename is a stub that is just used to prefix the error and so certain editors can annotate the original file.
Show all issues (including low priority ones)
By default, Credo's CLI output shows only the 5 most important issues per category. Using --all, you can show all the important issues in each category.
Use the --all-priorities switch to include low priority issues in the output (aliased as --strict).
Command line switches and config file
Most configuration options are also available as command line switches.
➜ mix credo suggest --help
Usage: mix credo suggest [paths] [options]
Suggests objects from every category that Credo thinks can be improved.
Examples:
$ mix credo suggest --format json
$ mix credo suggest lib/**/*.ex --only consistency --all
$ mix credo suggest --checks-without-tag formatter --checks-without-tag controversial
Arrows (↑ ↗ → ↘ ↓) hint at the importance of an issue.
Suggest options:
-a, --all Show all issues
-A, --all-priorities Show all issues including low priority ones
-c, --checks Only include checks that match the given strings
--checks-with-tag Only include checks that match the given tag (can be used multiple times)
--checks-without-tag Ignore checks that match the given tag (can be used multiple times)
--config-file Use the given config file
-C, --config-name Use the given config instead of "default"
--enable-disabled-checks Re-enable disabled checks that match the given strings
--files-included Only include these files (accepts globs, can be used multiple times)
--files-excluded Exclude these files (accepts globs, can be used multiple times)
--format Display the list in a specific format (json,flycheck,oneline)
-i, --ignore-checks Ignore checks that match the given strings
--ignore Alias for --ignore-checks
--min-priority Minimum priority to show issues (high,medium,normal,low,lower or number)
--mute-exit-status Exit with status zero even if there are issues
--only Alias for --checks
--strict Alias for --all-priorities
General options:
--[no-]color Toggle colored output
-v, --version Show version
-h, --help Show this help
Find advanced usage instructions and more examples here:
https://hexdocs.pm/credo/suggest_command.html
Give feedback and open an issue here:
https://github.com/rrrene/credo/issues
Some of these are not available as configuration options in .credo.exs:
--enable-disabled-checks [PATTERN]activates disabled checks on the fly--mute-exit-statusforces Credo to exit with an exit status of0