luacheck

static analyzer and linter for Lua

TLDR

Check a Lua file

$ luacheck [file.lua]

Check all Lua files in a directory recursively

$ luacheck [directory]

Check with a specific Lua standard

$ luacheck --std [lua53] [file.lua]

Ignore specific warning codes

$ luacheck --ignore [211] [file.lua]

Check showing warning codes in output

$ luacheck --codes [file.lua]

Output in a specific format

$ luacheck --formatter [TAP|JUnit|plain|visual_studio] [file.lua]

Check multiple files in parallel

$ luacheck -j [4] [file1.lua] [file2.lua]

Check from stdin with a custom filename

$ cat [file.lua] | luacheck --filename [file.lua] -

luacheck is a static analyzer and linter for Lua. It detects various issues including undefined globals, unused variables, unreachable code, and stylistic problems.luacheck supports multiple Lua versions and can be configured per-project via a .luacheckrc file or inline comments.

PARAMETERS

--std std

Set standard globals (lua51, lua52, lua53, lua54, luajit, ngx_lua, love, busted, min, max, none).

-g, --no-global

Exclude warnings about global variables.

-u, --no-unused

Exclude warnings about unused variables and values.

-r, --no-redefined

Exclude warnings about redefined variables.

-a, --no-unused-args

Exclude warnings about unused arguments and loop variables.

-s, --no-unused-secondaries

Exclude warnings about unused variables set alongside used ones.

-d, --allow-defined

Allow implicit global definitions via assignment.

-t, --allow-defined-top

Allow implicit global definitions at top level scope only.

-i, --ignore patt ...

Filter out warnings matching patterns.

-o, --only patt ...

Show only warnings matching patterns.

-e, --enable patt ...

Re-enable warnings matching patterns.

--globals names ...

Add custom allowed global variables.

--read-globals names ...

Add read-only global variables.

--max-line-length length

Set maximum line length (default: 120). Use --no-max-line-length to disable.

--max-cyclomatic-complexity limit

Set maximum cyclomatic complexity for functions.

--formatter fmt

Output format (default, TAP, JUnit, visual_studio, plain).

--codes

Show warning codes in output.

--ranges

Show column ranges for warnings.

-q, --quiet

Suppress output for files without warnings. Use -qq or -qqq for less output.

-j, --jobs num

Check files in parallel (requires LuaLanes).

--cache [file]

Enable caching of results (default: .luacheckcache).

--config file

Path to custom configuration file (default: .luacheckrc).

--no-config

Disable configuration file loading.

--no-color

Disable colorized output.

--exclude-files glob ...

Skip files matching these glob patterns.

--include-files glob ...

Only check files matching these glob patterns.

CONFIGURATION

$ -- .luacheckrc
std = "lua53"
globals = {"myGlobal"}
ignore = {"212"} -- unused argument
max_line_length = 120

CAVEATS

Static analysis only; won't catch runtime errors. May have false positives with dynamic code. Parallel checking with -j requires the LuaLanes library.

HISTORY

luacheck was created by Peter Melnichenko as a comprehensive Lua static analysis tool, filling the gap of linting tools for Lua.