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cspell

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CSpell is a comprehensive spell checker for code that helps catch spelling errors in source code, documentation, and comments designed specifically for developers and technical writers.

Key Features:

  • Code-Aware Checking: Understands programming languages and technical terminology, avoiding false positives on variable names, APIs, and technical terms
  • Multi-Language Support: Supports 30+ programming languages with specialized dictionaries for each language and framework
  • Custom Dictionaries: Extensive collection of domain-specific dictionaries (medical, scientific, legal, etc.) plus ability to create custom word lists
  • Flexible Configuration: Highly configurable via JSON files with support for workspace-specific settings and ignore patterns
  • Performance Optimized: Fast scanning designed for large codebases with minimal performance impact
  • Developer-Friendly: Handles camelCase, PascalCase, snake_case, and other programming conventions intelligently

MegaLinter generates content of a .cspell.json config file at the end of its TextReporter artifact. Copy it at the root of your repository, read it, remove real spelling errors (after have corrected them in the source), and you're good to go! If you do not want cspell to analyze the files names, define SPELL_CSPELL_ANALYZE_FILE_NAMES to false

cspell documentation

cspell - GitHub

Configuration in MegaLinter

Variable Description Default value
SPELL_CSPELL_ANALYZE_FILE_NAMES If set to true, MegaLinter will also send file names to cspell for analysis. Disable by defining SPELL_CSPELL_ANALYZE_FILE_NAMES to false true
SPELL_CSPELL_ARGUMENTS User custom arguments to add in linter CLI call
Ex: -s --foo "bar"
SPELL_CSPELL_COMMAND_REMOVE_ARGUMENTS User custom arguments to remove from command line before calling the linter
Ex: -s --foo "bar"
SPELL_CSPELL_FILTER_REGEX_INCLUDE Custom regex including filter
Ex: (src\|lib)
⚠️ Not available with SPELL_CSPELL_CLI_LINT_MODE = project
Exclude no file
SPELL_CSPELL_FILTER_REGEX_EXCLUDE Custom regex excluding filter
Ex: (test\|examples)
⚠️ Not available with SPELL_CSPELL_CLI_LINT_MODE = project
Exclude no file
SPELL_CSPELL_CLI_LINT_MODE Override default CLI lint mode
- file: Calls the linter for each file
- list_of_files: Call the linter with the list of files as argument
- project: Call the linter from the root of the project
list_of_files
SPELL_CSPELL_FORWARD_EXCLUDED_DIRECTORIES In project CLI lint mode, forward excluded directories (EXCLUDED_DIRECTORIES + ADDITIONAL_EXCLUDED_DIRECTORIES, and .gitignored directories when IGNORE_GITIGNORED_FILES is true) to the linter through its native exclusion arguments or generated ignore/config files true
SPELL_CSPELL_FILE_EXTENSIONS Allowed file extensions. "*" matches any extension, "" matches empty extension. Empty list excludes all files
Ex: [".py", ""]
Exclude every file
SPELL_CSPELL_FILE_NAMES_REGEX File name regex filters. Regular expression list for filtering files by their base names using regex full match. Empty list includes all files
Ex: ["Dockerfile(-.+)?", "Jenkinsfile"]
Include every file
SPELL_CSPELL_PRE_COMMANDS List of bash commands to run before the linter None
SPELL_CSPELL_POST_COMMANDS List of bash commands to run after the linter None
SPELL_CSPELL_UNSECURED_ENV_VARIABLES List of env variables explicitly not filtered before calling SPELL_CSPELL and its pre/post commands None
SPELL_CSPELL_CONFIG_FILE cspell configuration file name
Use LINTER_DEFAULT to let the linter find it
.cspell.json
SPELL_CSPELL_RULES_PATH Path where to find linter configuration file Workspace folder, then MegaLinter default rules
SPELL_CSPELL_DISABLE_ERRORS Run linter but consider errors as warnings false
SPELL_CSPELL_DISABLE_ERRORS_IF_LESS_THAN Maximum number of errors allowed 0
SPELL_CSPELL_TIMEOUT_SECONDS Maximum duration in seconds of the linter run, after which the linter process and its child processes are killed and reported as an error (exit code 124). Overrides LINTER_TIMEOUT_SECONDS. 0 disables the timeout 300
SPELL_CSPELL_CLI_EXECUTABLE Override CLI executable ['cspell']

IDE Integration

Use cspell in your favorite IDE to catch errors before MegaLinter !

IDE Extension Name Install
Visual Studio Code Code Spell Checker Install in VSCode

MegaLinter Flavors

This linter is available in the following flavors

Flavor Description Embedded linters Info
all Default MegaLinter Flavor 133 Docker Image Size (tag) Docker Pulls
c_cpp Optimized for pure C/C++ projects 59 Docker Image Size (tag) Docker Pulls
cupcake MegaLinter for the most commonly used languages 99 Docker Image Size (tag) Docker Pulls
documentation MegaLinter for documentation projects 52 Docker Image Size (tag) Docker Pulls
dotnet Optimized for C, C++, C# or VB based projects 66 Docker Image Size (tag) Docker Pulls
dotnetweb Optimized for C, C++, C# or VB based projects with JS/TS 81 Docker Image Size (tag) Docker Pulls
go Optimized for GO based projects 54 Docker Image Size (tag) Docker Pulls
java Optimized for JAVA based projects 57 Docker Image Size (tag) Docker Pulls
javascript Optimized for JAVASCRIPT or TYPESCRIPT based projects 68 Docker Image Size (tag) Docker Pulls
php Optimized for PHP based projects 57 Docker Image Size (tag) Docker Pulls
python Optimized for PYTHON based projects 69 Docker Image Size (tag) Docker Pulls
ruby Optimized for RUBY based projects 53 Docker Image Size (tag) Docker Pulls
rust Optimized for RUST based projects 53 Docker Image Size (tag) Docker Pulls
salesforce Optimized for Salesforce based projects 58 Docker Image Size (tag) Docker Pulls
swift Optimized for SWIFT based projects 53 Docker Image Size (tag) Docker Pulls
terraform Optimized for TERRAFORM based projects 57 Docker Image Size (tag) Docker Pulls

Behind the scenes

How are identified applicable files

  • If this linter is active, all files linted by all other active linters will be linted

How the linting is performed

cspell is called once on the whole project directory (project CLI lint mode)

  • filtering can not be done using MegaLinter configuration variables,it must be done using cspell configuration or ignore file (if existing)
  • VALIDATE_ALL_CODEBASE: false doesn't make cspell analyze only updated files

Example calls

cspell myfile.any
cspell -c cspell.json myfile.any

Help content

Usage: cspell [options] [command]

Spelling Checker for Code

Options:
  -V, --version                         output the version number
  -h, --help                            display help for command

Commands:
  lint [options] [globs...]             Check spelling
  trace [options] [words...]            Trace words -- Search for words in the
                                        configuration and dictionaries.
  check [options] <files...>            Spell check file(s) and display the
                                        result. The full file is displayed in
                                        color.
  suggestions|sug [options] [words...]  Spelling Suggestions for words.
  init [options]                        Initialize a CSpell configuration file.
  link                                  Link dictionaries and other settings to
                                        the cspell global config.
  dictionaries [options]                List dictionaries
  help [command]                        display help for command

Options for "lint" (the default command):
  -c, --config <cspell.json>     Configuration file to use.  By default cspell
                                 looks for cspell.json in the current directory.
  --no-config-search             Disable automatic searching for additional
                                 configuration files in parent directories. Only
                                 the specified config file (if any) will be
                                 used.
  --stop-config-search-at <dir>  Specify a directory at which to stop searching
                                 for configuration files when walking up from
                                 the files being checked. Useful for limiting
                                 config inheritance.
  -v, --verbose                  Display more information about the files being
                                 checked. Add more than one -v for increased
                                 verbosity.
  --locale <locale>              Set language locales. i.e. "en,fr" for English
                                 and French, or "en-GB" for British English.
  --language-id <file-type>      Force programming language for unknown
                                 extensions. i.e. "php" or "scala"
  --words-only                   Only output the words not found in the
                                 dictionaries.
  -u, --unique                   Only output the first instance of a word not
                                 found in the dictionaries.
  -e, --exclude <glob>           Exclude files matching the glob pattern. This
                                 option can be used multiple times to add
                                 multiple globs.
  --file-list <path or stdin>    Specify a list of files to be spell checked.
                                 The list is filtered against the glob file
                                 patterns. Note: the format is 1 file path per
                                 line.
  --file [file...]               Specify files to spell check. They are filtered
                                 by the [globs...].
  --force-check                  Force the --file or --file-list documents to be
                                 checked even if it would normally be excluded.
  --follow-symlinks              Allow checking --file and --file-list documents
                                 referenced by symbolic links.
  --no-issues                    Do not show the spelling errors.
  --no-progress                  Turn off progress messages
  --no-summary                   Turn off summary message in console.
  -s, --silent                   Silent mode, suppress error messages.
  --no-exit-code                 Do not return an exit code if issues are found.
  --quiet                        Only show spelling issues or errors.
  --fail-fast                    Exit after first file with an issue or error.
  --continue-on-error            Continue processing files even if there is a
                                 configuration error.
  -r, --root <root folder>       Root directory, defaults to current directory.
  --no-relative                  Issues are displayed with absolute path instead
                                 of relative to the root.
  --show-context                 Show the surrounding text around an issue.
  --show-suggestions             Show spelling suggestions.
  --no-show-suggestions          Do not show spelling suggestions or fixes.
  --no-must-find-files           Do not error if no files are found.
  --cache                        Use cache to only check changed files.
  --no-cache                     Do not use cache.
  --cache-reset                  Reset the cache file.
  --cache-strategy <strategy>    Strategy to use for detecting changed files.
                                 (choices: "content", "metadata", default:
                                 "content")
  --cache-location <path>        Path to the cache file or directory. (default:
                                 ".cspellcache")
  --dot                          Include files and directories starting with `.`
                                 (period) when matching globs.
  --glob-symlinks                Follow symbolic links when matching globs.
  --gitignore                    Ignore files matching glob patterns found in
                                 .gitignore files.
  --no-gitignore                 Do NOT use .gitignore files.
  --gitignore-root <path>        Prevent searching for .gitignore files past
                                 root.
  --validate-directives          Validate in-document CSpell directives.
  --max-file-size <size>         Prevent checking large files. i.e 1MB, 50KB,
                                 1GB
  --color                        Force color.
  --no-color                     Turn off color.
  --no-default-configuration     Do not load the default configuration and
                                 dictionaries.
  --dictionary <name>            Enable a dictionary by name.
  --disable-dictionary <name>    Disable a dictionary by name.
  --reporter <module|path>       Specify one or more reporters to use.
  --report <level>               Set how unknown words are reported (choices:
                                 "all", "simple", "typos", "flagged")
  --issue-template [template]    Use a custom issue template. See --help
                                 --issue-template for details.

More Examples:

    cspell "**/*.js" --reporter @cspell/cspell-json-reporter
        This will spell check all ".js" files recursively and use
        "@cspell/cspell-json-reporter".

    cspell . --reporter default
        This will force the default reporter to be used overriding
        any reporters defined in the configuration.

    cspell . --reporter ./<path>/reporter.cjs
        Use a custom reporter. See API for details.

    cspell "*.md" --exclude CHANGELOG.md --files README.md CHANGELOG.md
        Spell check only check "README.md" but NOT "CHANGELOG.md".

    cspell "/*.md" --no-must-find-files --files $FILES
        Only spell check the "/*.md" files in $FILES,
        where $FILES is a shell variable containing the list of files.

    cspell --help --verbose
        Show all options including hidden options.

References:
    https://cspell.org
    https://github.com/streetsidesoftware/cspell

Installation on mega-linter Docker image

  • Dockerfile commands :
    # renovate: datasource=npm depName=cspell
    ARG NPM_CSPELL_VERSION=10.4.0
    

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