uncrustify

Configurable multi-language source code formatter

TLDR

Format a file and output to stdout

$ uncrustify -c [config.cfg] -f [source.c]

Format and write to output file

$ uncrustify -c [config.cfg] -f [source.c] -o [output.c]

Format files in place with backup

$ uncrustify -c [config.cfg] --replace [file1.c] [file2.c]

Format files in place without backup

$ uncrustify -c [config.cfg] --no-backup [*.c]

Specify language explicitly

$ uncrustify -c [config.cfg] -l [CPP] -f [source.cpp]

Generate default configuration

$ uncrustify --show-config > [uncrustify.cfg]

Process files from a list

$ uncrustify -c [config.cfg] -F [filelist.txt]

SYNOPSIS

uncrustify [options] [files ...]

uncrustify is a highly configurable source code beautifier for C, C++, C#, Objective-C, D, Java, Pawn, and VALA. It automatically formats code according to specified style rules controlling indentation, spacing, alignment, and line breaks.
Configuration is controlled through a configuration file with hundreds of options. The default location is $UNCRUSTIFY_CONFIG or ~/.uncrustify.cfg. Generate a starting configuration with --show-config and customize incrementally.
uncrustify can process single files, file lists, or entire source trees. It supports in-place editing with optional backups.

PARAMETERS

-c cfg

Use specified configuration file (or '-' for defaults).

-f file

Process single file, output to stdout.

-o file

Write output to specified file.

-F file

Read list of files to process (one per line, '-' for stdin).

-l lang

Language override: C, CPP, D, CS, JAVA, PAWN, VALA, OC, OC+.

--replace

Replace source files in place (creates backup).

--no-backup

Replace files without backup.

--mtime

Preserve modification time on replaced files.

--frag

Treat input as code fragment with proper first-line indent.

--show-config

Print active configuration to stdout.

--update-config

Output new config file with current settings.

--update-config-with-doc

Output config file with usage comments.

--set key=value

Override configuration option.

-q

Quiet mode, no stderr output.

-h, --help

Display help message.

--version

Display version information.

CONFIGURATION

$UNCRUSTIFY_CONFIG

Environment variable specifying the path to the configuration file.

~/.uncrustify.cfg

Default user configuration file used when no -c option or environment variable is set.

CAVEATS

Configuration complexity is high; start with generated defaults and adjust gradually. Different code styles may require extensive configuration tuning. Always test on a backup or version-controlled code before using --no-backup.

HISTORY

uncrustify was created by Ben Gardner and first released in 2005. It was designed to be a highly flexible code formatter supporting multiple languages. The project has grown to support over 700 configuration options, making it one of the most configurable code formatters available.