Command reference

This page lists every built-in sdb command, grouped by domain. Use help <command> inside the REPL for full details and examples.

Core commands

These are defined in sdb/command.py and are always available.

Command	Aliases	Description
address	addr	Resolve symbol names or hex addresses to drgn objects; can start a pipeline.
cast		Cast pipeline objects to a specified C type.
deref		Dereference pointer objects.
walk		Dispatch to the appropriate Walker based on input type. With no input, lists all registered walkers.

General commands

Utility commands available for all target types.

Command	Aliases	Description
echo	cc	Create void * objects from raw numeric addresses.
member		Access struct members using ., ->, or [] syntax.
filter		Filter objects by a Python expression (obj refers to the current object).
pyfilter		Alias / variant of filter with Python expressions.
head		Pass through only the first N objects.
tail		Pass through only the last N objects.
count	cnt, wc	Count objects in the pipeline and emit the result.
sum		Sum integer values in the pipeline.
type		Print the drgn type of each input object.
ptype		Print the type definition (struct layout, enum values, etc.).
sizeof		Print the size of a type in bytes.
container_of		Given a pointer to a struct member, find the containing struct.
array		Index into array objects.
print		Format output for scripts (machine-readable).
pretty_print	pp	Pretty-print objects using the registered PrettyPrinter for their type.
help	man	Show help for a command.
history		Show REPL command history.
exit	quit	Exit the REPL.

Linux kernel commands

Available when debugging a kernel target (live or crash dump).

Threads and stacks

Command	Aliases	Description
threads	thread	Locate and print kernel threads (task_struct).
stacks	stack	Print aggregated stack traces for threads. Supports filtering by state (-t), function (-c), and module (-m).
crashed_thread	panic_stack, panic_thread	Print the thread that panicked (crash dumps only).
trace	bt	Print a backtrace for a task_struct.
stackframe	frame, f	Select or print a stack frame for a task.
locals	local	Print local variables in the current stack frame.
registers	register	Print register values for a stack frame.

Processes

Command	Aliases	Description
find_task		Find a task_struct by PID.
pid		Find a struct pid by PID number.
fget		Get a struct file * from a file descriptor for a task.

Memory

Command	Aliases	Description
slabs		List slab caches (kmem_cache).
slub_cache		Walk objects in a SLUB slab cache.
percpu		Resolve a per-CPU pointer for a given CPU.
cpu_counter_sum		Sum a per-CPU counter across all CPUs.
whatis		Identify which kmem cache owns an address.

Data structure walkers

Command	Aliases	Description
linux_list	lxlist	Walk a struct list_head linked list.
linux_hlist	lxhlist	Walk a struct hlist_head hash list.
rbtree		Walk a red-black tree.

System

Command	Aliases	Description
dmesg		Print the kernel log buffer.

ZFS commands

Available when the ZFS kernel module is loaded.

Command	Aliases	Description
spa		Locate and pretty-print SPA (Storage Pool Allocator) objects.
vdev		Walk and pretty-print vdevs in a pool.
metaslab		Walk metaslabs for a vdev.
zio		Iterate and pretty-print ZIO (ZFS I/O) objects.
dbuf		Iterate and pretty-print dbufs (DMU buffers).
arc		Print ARC (Adaptive Replacement Cache) statistics.
zfs_btree		Walk a ZFS B-tree.
blkptr		Pretty-print a ZFS block pointer.
range_tree		Pretty-print a range tree.
range_seg		Locate range segments from a range tree.
zfs_histogram	zhist	Print a ZFS histogram and its median.
zfs_dbgmsg		Print ZFS debug messages.

SPL commands

Commands for the Solaris Porting Layer data structures.

Command	Aliases	Description
avl		Walk an AVL tree (avl_tree_t).
spl_list		Walk an SPL list_t.
multilist		Walk a multilist.
spl_kmem_caches		List SPL kmem caches.
spl_cache		Walk objects in an SPL kmem cache.

Meta-commands

Meta-commands are prefixed with % and control the REPL itself rather than operating on drgn objects.

Command	Description
%load-commands <path>	Load external sdb commands from a file or directory.
%session record <file>	Start recording memory accesses to <file>.vmcore.recorded.
%session stop	Stop recording and save the vmcore.
%session status	Show recording/replay status and statistics.
%session config [option] [value]	Configure output format and compression.
%session snapshot <var> [--depth N]	Capture an object’s memory into the recording.
%session record-memory <addr> <size>	Capture a raw memory region into the recording.
%session load <file>	Hint to use --replay for loading recorded sessions.