Configuration

catter CLI

catter [options] <script> [script-args] -- <build-command>

Options

Option	Description	Default
-m, --mode <mode>	Runtime mode. Controls how catter intercepts processes.	inject
-d, --dir <path>	Working directory for the target process.	Current directory
--stdio-mode <mode>	How to handle child process stdio. See below.	inherit
-h, --help	Show help message.

--stdio-mode

Controls what happens with the intercepted process's standard output and error streams:

• inherit -- Real-time passthrough. Build output appears in your terminal as it normally would.
• capture -- Buffer stdout and stderr. The captured output is made available to the script's onFinish callback instead of being printed immediately.

Script Specification

Built-in scripts use the script:: prefix:

catter script::<name> [script-args] -- <build-command>

Available built-in scripts:

Name	Description
script::cdb	Generate compile_commands.json
script::cmd-tree	Display the build command tree
script::target-tree	Display the build target tree

Custom scripts use a file path:

catter ./path/to/script.js [script-args] -- <build-command>

catter-proxy CLI

WARNING

catter-proxy is an internal component. It is invoked automatically by catter and is not intended for direct use.

catter-proxy [options] -- <command>

Option	Description
-p <id>	Parent process ID for IPC session
<executable>	Resolved executable path

Environment Variables

These variables are set automatically by catter at runtime. They are documented here for reference; you should not need to set them manually.

Unix (Linux / macOS)

Variable	Purpose
__key_catter_proxy_path_v1	Path to the catter-proxy executable
__key_catter_command_id_v1	IPC command identifier
LD_PRELOAD (Linux)	Injects the catter hook shared library
DYLD_INSERT_LIBRARIES (macOS)	Injects the catter hook shared library

Windows

Variable	Purpose
CATTER_IPC_ID	IPC session identifier
CATTER_PROXY_PATH	Path to the catter-proxy executable