candump1

Manual page for candump 2023.03-1

Usage

candump [options] <CAN interface>+

Overview

candump - dump CAN bus traffic.

: (use CTRL-C to terminate candump)

Options

-t <type>: (timestamp: (a)bsolute/(d)elta/(z)ero/(A)bsolute w date)

-H: (read hardware timestamps instead of system timestamps)

-c: (increment color mode level)

-i: (binary output - may exceed 80 chars/line)

-a: (enable additional ASCII output)

-S: (swap byte order in printed CAN data[] - marked with '`' )

-s <level>: (silent mode - 0: off (default) 1: animation 2: silent)

-l: (log CAN-frames into file. Sets '-s 2' by default)

-f <fname>: (log CAN-frames into file <fname>. Sets '-s 2' by default)

-L: (use log file format on stdout)

-n <count>: (terminate after reception of <count> CAN frames)

-r <size>: (set socket receive buffer to <size>)

-D: (Don't exit if a "detected" can device goes down)

-d: (monitor dropped CAN frames)

-e: (dump CAN error frames in human-readable format)

-8: (display raw DLC values in {} for Classical CAN)

-x: (print extra message infos, rx/tx brs esi)

-T <msecs>: (terminate after <msecs> if no frames were received)

Up to 16 CAN interfaces with optional filter sets can be specified on the commandline in the form: <ifname>[,filter]*

Filters:

	Comma separated filters can be specified for each given CAN interface:
	<can_id>:<can_mask>
	(matches when <received_can_id> & mask == can_id & mask)
	<can_id>~<can_mask>
	(matches when <received_can_id> & mask != can_id & mask)
	#<error_mask>
	(set error frame filter, see include/linux/can/error.h)
	[j\|J]
	(join the given CAN filters - logical AND semantic)

CAN IDs, masks and data content are given and expected in hexadecimal values. When the can_id is 8 digits long the CAN_EFF_FLAG is set for 29 bit EFF format. Without any given filter all data frames are received ('0:0' default filter).

Use interface name 'any' to receive from all CAN interfaces.

Examples

candump -c -c -ta can0,123:7FF,400:700,#000000FF can2,400~7F0 can3 can8

candump -l any,0~0,#FFFFFFFF

: (log only error frames but no(!) data frames)

candump -l any,0:0,#FFFFFFFF

: (log error frames and also all data frames)

candump vcan2,12345678:DFFFFFFF

: (match only for extended CAN ID 12345678)

candump vcan2,123:7FF

: (matches CAN ID 123 - including EFF and RTR frames)

candump vcan2,123:C00007FF

: (matches CAN ID 123 - only SFF and non-RTR frames)

Releases

4 releases since Debian 10 (Buster); the text changed 2 times.

-8 since Debian 13 (Trixie); -f since Debian 13 (Trixie).

-B until Debian 10 (Buster); -b until Debian 10 (Buster); -u until Debian 10 (Buster).