dbg Debugger dbg is a CLI debugger that supports Node.js (V8/CDP), Bun (WebKit/JSC), and native code (C/C++/Rust/Swift via LLDB/DAP). It uses short @refs for all entities -- use them instead of long IDs. Supported Runtimes Runtime Language Launch example Node.js JavaScript dbg launch --brk node app.js tsx / ts-node TypeScript dbg launch --brk tsx src/app.ts Bun JavaScript / TypeScript dbg launch --brk bun app.ts LLDB C / C++ / Rust / Swift dbg launch --brk --runtime lldb ./program The runtime is auto-detected from the launch command for JS runtimes. For native code, use --runtime lldb . Core Debug Loop

1. Launch with breakpoint at first line

dbg launch --brk node app.js

Or: dbg launch --brk bun app.ts

Or: dbg launch --brk --runtime lldb ./my_program

Or attach to a running process with the --inspect flag

dbg attach 9229

2. Set breakpoints at suspicious locations

dbg break src/handler.ts:42 dbg break src/utils.ts:15 --condition "count > 10"

3. Run to breakpoint

dbg continue

4. Inspect state (shows location, source, locals, stack)

dbg state

5. Drill into values

dbg props @v1

expand object

dbg props @v1 --depth 3

expand nested 3 levels

dbg eval "x + 1"

6. Fix and verify (JS/TS only)

dbg set count 0

change variable

dbg hotpatch src/utils.js

live-edit (reads file from disk)

dbg continue

verify fix

Debugging Strategies Bug investigation -- narrow down with breakpoints dbg launch --brk node app.js dbg break src/api.ts:50

suspect line

dbg break src/api.ts:60 --condition "!user"

conditional

dbg continue dbg vars

check locals

dbg eval "JSON.stringify(req.body)"

inspect deeply

dbg step over

advance one line

dbg state

see new state

Native code debugging (C/C++/Rust) dbg launch --brk --runtime lldb ./my_program dbg break main.c:42 dbg break-fn main

function breakpoint (DAP only)

dbg continue dbg vars

inspect locals

dbg eval "array[i]"

evaluate expression

dbg step into

step into function

Attach to running/test process

Start with inspector enabled

node --inspect app.js

Or: bun --inspect app.ts

Then attach

dbg attach 9229 dbg state Trace execution flow with logpoints (no pause) dbg logpoint src/auth.ts:20 "login attempt: ${username} " dbg logpoint src/auth.ts:45 "auth result: ${result} " dbg continue dbg console

see logged output

Exception debugging dbg catch uncaught

pause on uncaught exceptions

dbg continue

runs until exception

dbg state

see where it threw

dbg eval "err.message"

inspect the error

dbg stack

full call stack

TypeScript source map support dbg automatically resolves .ts paths via source maps. Set breakpoints using .ts paths, see .ts source in output. Use --generated to see compiled .js if needed. Ref System Every output assigns short refs. Use them everywhere: @v1..@vN -- variables: dbg props @v1 , dbg set @v2 true @f0..@fN -- stack frames: dbg eval --frame @f1 "this" BP#1..N -- breakpoints: dbg break-rm BP#1 , dbg break-toggle BP#1 LP#1..N -- logpoints: dbg break-rm LP#1 Refs @v / @f reset on each pause. BP# / LP# persist until removed. Key Flags --json -- machine-readable JSON output on any command --session NAME -- target a specific session (default: "default") --runtime NAME -- select debug adapter (e.g. lldb for native code) --generated -- bypass source maps, show compiled JS (on state/source/stack) Command Reference See references/commands.md for full command details and options. Tips dbg state after stepping always shows location + source + locals -- usually enough context dbg state -c for source only, -v for vars only, -s for stack only -- save tokens dbg eval supports await -- useful for async inspection (JS/TS) dbg blackbox "node_modules/**" -- skip stepping into dependencies dbg hotpatch file reads the file from disk -- edit the file first, then hotpatch (JS/TS only) dbg break-fn funcName -- function breakpoints work with DAP runtimes (LLDB) Execution commands ( continue , step , pause , run-to ) auto-return status dbg stop kills the debugged process and daemon