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Configuration and Command History

If $XDG_CONFIG_HOME is set, then configuration and command history files are located in $XDG_CONFIG_HOME/dlv. Otherwise, they are located in $HOME/.config/dlv on Linux and $HOME/.dlv on other systems.

The configuration file config.yml contains all the configurable options and their default values. The command history is stored in .dbg_history.

Commands

Running the program

Command Description
call Resumes process, injecting a function call (EXPERIMENTAL!!!)
continue Run until breakpoint or program termination.
next Step over to next source line.
next-instruction Single step a single cpu instruction, skipping function calls.
rebuild Rebuild the target executable and restarts it. It does not work if the executable was not built by delve.
restart Restart process.
rev Reverses the execution of the target program for the command specified.
rewind Run backwards until breakpoint or start of recorded history.
step Single step through program.
step-instruction Single step a single cpu instruction.
stepout Step out of the current function.

Manipulating breakpoints

Command Description
break Sets a breakpoint.
breakpoints Print out info for active breakpoints.
clear Deletes breakpoint.
clearall Deletes multiple breakpoints.
condition Set breakpoint condition.
on Executes a command when a breakpoint is hit.
toggle Toggles on or off a breakpoint.
trace Set tracepoint.
watch Set watchpoint.

Viewing program variables and memory

Command Description
args Print function arguments.
display Print value of an expression every time the program stops.
examinemem Examine raw memory at the given address.
locals Print local variables.
print Evaluate an expression.
regs Print contents of CPU registers.
set Changes the value of a variable.
vars Print package variables.
whatis Prints type of an expression.

Listing and switching between threads and goroutines

Command Description
goroutine Shows or changes current goroutine
goroutines List program goroutines.
thread Switch to the specified thread.
threads Print out info for every traced thread.

Viewing the call stack and selecting frames

Command Description
deferred Executes command in the context of a deferred call.
down Move the current frame down.
frame Set the current frame, or execute command on a different frame.
stack Print stack trace.
up Move the current frame up.

Other commands

Command Description
check Creates a checkpoint at the current position.
checkpoints Print out info for existing checkpoints.
clear-checkpoint Deletes checkpoint.
config Changes configuration parameters.
disassemble Disassembler.
dump Creates a core dump from the current process state
edit Open where you are in $DELVE_EDITOR or $EDITOR
exit Exit the debugger.
funcs Print list of functions.
help Prints the help message.
libraries List loaded dynamic libraries
list Show source code.
packages Print list of packages.
source Executes a file containing a list of delve commands
sources Print list of source files.
target Manages child process debugging.
transcript Appends command output to a file.
types Print list of types

args

Print function arguments.

[goroutine <n>] [frame <m>] args [-v] [<regex>]

If regex is specified only function arguments with a name matching it will be returned. If -v is specified more information about each function argument will be shown.

break

Sets a breakpoint.

break [name] [locspec] [if <condition>]

Locspec is a location specifier in the form of:

  • *<address> Specifies the location of memory address address. address can be specified as a decimal, hexadecimal or octal number
  • <filename>:<line> Specifies the line in filename. filename can be the partial path to a file or even just the base name as long as the expression remains unambiguous.
  • <line> Specifies the line in the current file
  • +<offset> Specifies the line offset lines after the current one
  • -<offset> Specifies the line offset lines before the current one
  • <function>[:<line>] Specifies the line inside function. The full syntax for function is <package>.(*<receiver type>).<function name> however the only required element is the function name, everything else can be omitted as long as the expression remains unambiguous. For setting a breakpoint on an init function (ex: main.init), the <filename>:<line> syntax should be used to break in the correct init function at the correct location.
  • /<regex>/ Specifies the location of all the functions matching regex

If locspec is omitted a breakpoint will be set on the current line.

If you would like to assign a name to the breakpoint you can do so with the form:

break mybpname main.go:4

Finally, you can assign a condition to the newly created breakpoint by using the 'if' postfix form, like so:

break main.go:55 if i == 5

Alternatively you can set a condition on a breakpoint after created by using the 'on' command.

See also: "help on", "help cond" and "help clear"

Aliases: b

breakpoints

Print out info for active breakpoints.

breakpoints [-a]

Specifying -a prints all physical breakpoint, including internal breakpoints.

Aliases: bp

call

Resumes process, injecting a function call (EXPERIMENTAL!!!)

call [-unsafe] <function call expression>

Current limitations:

  • only pointers to stack-allocated objects can be passed as argument.
  • only some automatic type conversions are supported.
  • functions can only be called on running goroutines that are not executing the runtime.
  • the current goroutine needs to have at least 256 bytes of free space on the stack.
  • functions can only be called when the goroutine is stopped at a safe point.
  • calling a function will resume execution of all goroutines.
  • only supported on linux's native backend.

check

Creates a checkpoint at the current position.

checkpoint [note]

The "note" is arbitrary text that can be used to identify the checkpoint, if it is not specified it defaults to the current filename:line position.

Aliases: checkpoint

checkpoints

Print out info for existing checkpoints.

clear

Deletes breakpoint.

clear <breakpoint name or id>

clear-checkpoint

Deletes checkpoint.

clear-checkpoint <id>

Aliases: clearcheck

clearall

Deletes multiple breakpoints.

clearall [<locspec>]

If called with the locspec argument it will delete all the breakpoints matching the locspec. If locspec is omitted all breakpoints are deleted.

condition

Set breakpoint condition.

condition <breakpoint name or id> <boolean expression>.
condition -hitcount <breakpoint name or id> <operator> <argument>.
condition -per-g-hitcount <breakpoint name or id> <operator> <argument>.
condition -clear <breakpoint name or id>.

Specifies that the breakpoint, tracepoint or watchpoint should break only if the boolean expression is true.

See Documentation/cli/expr.md for a description of supported expressions.

With the -hitcount option a condition on the breakpoint hit count can be set, the following operators are supported

condition -hitcount bp > n
condition -hitcount bp >= n
condition -hitcount bp < n
condition -hitcount bp <= n
condition -hitcount bp == n
condition -hitcount bp != n
condition -hitcount bp % n

The -per-g-hitcount option works like -hitcount, but use per goroutine hitcount to compare with n.

With the -clear option a condition on the breakpoint can removed.

The '% n' form means we should stop at the breakpoint when the hitcount is a multiple of n.

Examples:

cond 2 i == 10				breakpoint 2 will stop when variable i equals 10
cond name runtime.curg.goid == 5	breakpoint 'name' will stop only on goroutine 5
cond -clear 2				the condition on breakpoint 2 will be removed

Aliases: cond

config

Changes configuration parameters.

config -list

Show all configuration parameters.

config -save

Saves the configuration file to disk, overwriting the current configuration file.

config <parameter> <value>

Changes the value of a configuration parameter.

config substitute-path <from> <to>
config substitute-path <from>
config substitute-path -clear

Adds or removes a path substitution rule, if -clear is used all substitute-path rules are removed. Without arguments shows the current list of substitute-path rules. See also Documentation/cli/substitutepath.md for how the rules are applied.

config alias <command> <alias>
config alias <alias>

Defines <alias> as an alias to <command> or removes an alias.

config debug-info-directories -add <path>
config debug-info-directories -rm <path>
config debug-info-directories -clear

Adds, removes or clears debug-info-directories.

continue

Run until breakpoint or program termination.

continue [<locspec>]

Optional locspec argument allows you to continue until a specific location is reached. The program will halt if a breakpoint is hit before reaching the specified location.

For example:

continue main.main
continue encoding/json.Marshal

Aliases: c

deferred

Executes command in the context of a deferred call.

deferred <n> <command>

Executes the specified command (print, args, locals) in the context of the n-th deferred call in the current frame.

disassemble

Disassembler.

[goroutine <n>] [frame <m>] disassemble [-a <start> <end>] [-l <locspec>]

If no argument is specified the function being executed in the selected stack frame will be executed.

-a <start> <end>	disassembles the specified address range
-l <locspec>		disassembles the specified function

Aliases: disass

display

Print value of an expression every time the program stops.

display -a [%format] <expression>
display -d <number>

The '-a' option adds an expression to the list of expression printed every time the program stops. The '-d' option removes the specified expression from the list.

If display is called without arguments it will print the value of all expression in the list.

down

Move the current frame down.

down [<m>]
down [<m>] <command>

Move the current frame down by <m>. The second form runs the command on the given frame.

dump

Creates a core dump from the current process state

dump <output file>

The core dump is always written in ELF, even on systems (windows, macOS) where this is not customary. For environments other than linux/amd64 threads and registers are dumped in a format that only Delve can read back.

edit

Open where you are in $DELVE_EDITOR or $EDITOR

edit [locspec]

If locspec is omitted edit will open the current source file in the editor, otherwise it will open the specified location.

Aliases: ed

examinemem

Examine raw memory at the given address.

Examine memory:

examinemem [-fmt <format>] [-count|-len <count>] [-size <size>] <address>
examinemem [-fmt <format>] [-count|-len <count>] [-size <size>] -x <expression>

Format represents the data format and the value is one of this list (default hex): bin(binary), oct(octal), dec(decimal), hex(hexadecimal) and raw. Length is the number of bytes (default 1) and must be less than or equal to 1000. Address is the memory location of the target to examine. Please note '-len' is deprecated by '-count and -size'. Expression can be an integer expression or pointer value of the memory location to examine.

For example:

x -fmt hex -count 20 -size 1 0xc00008af38
x -fmt hex -count 20 -size 1 -x 0xc00008af38 + 8
x -fmt hex -count 20 -size 1 -x &myVar
x -fmt hex -count 20 -size 1 -x myPtrVar

Aliases: x

exit

Exit the debugger.

exit [-c]

When connected to a headless instance started with the --accept-multiclient, pass -c to resume the execution of the target process before disconnecting.

Aliases: quit q

frame

Set the current frame, or execute command on a different frame.

frame <m>
frame <m> <command>

The first form sets frame used by subsequent commands such as "print" or "set". The second form runs the command on the given frame.

funcs

Print list of functions.

funcs [<regex>]

If regex is specified only the functions matching it will be returned.

goroutine

Shows or changes current goroutine

goroutine
goroutine <id>
goroutine <id> <command>

Called without arguments it will show information about the current goroutine. Called with a single argument it will switch to the specified goroutine. Called with more arguments it will execute a command on the specified goroutine.

Aliases: gr

goroutines

List program goroutines.

goroutines [-u|-r|-g|-s] [-t [depth]] [-l] [-with loc expr] [-without loc expr] [-group argument] [-chan expr] [-exec command]

Print out info for every goroutine. The flag controls what information is shown along with each goroutine:

-u	displays location of topmost stackframe in user code (default)
-r	displays location of topmost stackframe (including frames inside private runtime functions)
-g	displays location of go instruction that created the goroutine
-s	displays location of the start function
-t	displays goroutine's stacktrace (an optional depth value can be specified, default: 10)
-l	displays goroutine's labels

If no flag is specified the default is -u, i.e. the first frame within the first 30 frames that is not executing a runtime private function.

FILTERING

If -with or -without are specified only goroutines that match the given condition are returned.

To only display goroutines where the specified location contains (or does not contain, for -without and -wo) expr as a substring, use:

goroutines -with (userloc|curloc|goloc|startloc) expr
goroutines -w (userloc|curloc|goloc|startloc) expr
goroutines -without (userloc|curloc|goloc|startloc) expr
goroutines -wo (userloc|curloc|goloc|startloc) expr

Where:
userloc: filter by the location of the topmost stackframe in user code
curloc: filter by the location of the topmost stackframe (including frames inside private runtime functions)
goloc: filter by the location of the go instruction that created the goroutine
startloc: filter by the location of the start function

To only display goroutines that have (or do not have) the specified label key and value, use:

goroutines -with label key=value
goroutines -without label key=value

To only display goroutines that have (or do not have) the specified label key, use:

goroutines -with label key
goroutines -without label key

To only display goroutines that are running (or are not running) on a OS thread, use:

goroutines -with running
goroutines -without running

To only display user (or runtime) goroutines, use:

goroutines -with user
goroutines -without user

CHANNELS

To only show goroutines waiting to send to or receive from a specific channel use:

goroutines -chan expr

Note that 'expr' must not contain spaces.

GROUPING

goroutines -group (userloc|curloc|goloc|startloc|running|user)

Where:
userloc: groups goroutines by the location of the topmost stackframe in user code
curloc: groups goroutines by the location of the topmost stackframe
goloc: groups goroutines by the location of the go instruction that created the goroutine
startloc: groups goroutines by the location of the start function
running: groups goroutines by whether they are running or not
user: groups goroutines by weather they are user or runtime goroutines

Groups goroutines by the given location, running status or user classification, up to 5 goroutines per group will be displayed as well as the total number of goroutines in the group.

goroutines -group label key

Groups goroutines by the value of the label with the specified key.

EXEC

goroutines -exec <command>

Runs the command on every goroutine.

Aliases: grs

help

Prints the help message.

help [command]

Type "help" followed by the name of a command for more information about it.

Aliases: h

libraries

List loaded dynamic libraries

list

Show source code.

[goroutine <n>] [frame <m>] list [<locspec>]

Show source around current point or provided locspec.

For example:

frame 1 list 69
list testvariables.go:10000
list main.main:30
list 40

Aliases: ls l

locals

Print local variables.

[goroutine <n>] [frame <m>] locals [-v] [<regex>]

The name of variables that are shadowed in the current scope will be shown in parenthesis.

If regex is specified only local variables with a name matching it will be returned. If -v is specified more information about each local variable will be shown.

next

Step over to next source line.

next [count]

Optional [count] argument allows you to skip multiple lines.

Aliases: n

next-instruction

Single step a single cpu instruction, skipping function calls.

Aliases: ni nexti

on

Executes a command when a breakpoint is hit.

on <breakpoint name or id> <command>
on <breakpoint name or id> -edit

Supported commands: print, stack, goroutine, trace and cond. To convert a breakpoint into a tracepoint use:

on <breakpoint name or id> trace

The command 'on <bp> cond <cond-arguments>' is equivalent to 'cond <bp> <cond-arguments>'.

The command 'on x -edit' can be used to edit the list of commands executed when the breakpoint is hit.

packages

Print list of packages.

packages [<regex>]

If regex is specified only the packages matching it will be returned.

print

Evaluate an expression.

[goroutine <n>] [frame <m>] print [%format] <expression>

See Documentation/cli/expr.md for a description of supported expressions.

The optional format argument is a format specifier, like the ones used by the fmt package. For example "print %x v" will print v as an hexadecimal number.

Aliases: p

rebuild

Rebuild the target executable and restarts it. It does not work if the executable was not built by delve.

regs

Print contents of CPU registers.

regs [-a]

Argument -a shows more registers. Individual registers can also be displayed by 'print' and 'display'. See Documentation/cli/expr.md.

restart

Restart process.

For recorded targets the command takes the following forms:

restart					resets to the start of the recording
restart [checkpoint]			resets the recording to the given checkpoint
restart -r [newargv...]	[redirects...]	re-records the target process

For live targets the command takes the following forms:

restart [newargv...] [redirects...]	restarts the process

If newargv is omitted the process is restarted (or re-recorded) with the same argument vector. If -noargs is specified instead, the argument vector is cleared.

A list of file redirections can be specified after the new argument list to override the redirections defined using the '--redirect' command line option. A syntax similar to Unix shells is used:

<input.txt	redirects the standard input of the target process from input.txt
>output.txt	redirects the standard output of the target process to output.txt
2>error.txt	redirects the standard error of the target process to error.txt

Aliases: r

rev

Reverses the execution of the target program for the command specified. Currently, rev next, step, step-instruction and stepout commands are supported.

rewind

Run backwards until breakpoint or start of recorded history.

Aliases: rw

set

Changes the value of a variable.

[goroutine <n>] [frame <m>] set <variable> = <value>

See Documentation/cli/expr.md for a description of supported expressions. Only numerical variables and pointers can be changed.

source

Executes a file containing a list of delve commands

source <path>

If path ends with the .star extension it will be interpreted as a starlark script. See Documentation/cli/starlark.md for the syntax.

If path is a single '-' character an interactive starlark interpreter will start instead. Type 'exit' to exit.

sources

Print list of source files.

sources [<regex>]

If regex is specified only the source files matching it will be returned.

stack

Print stack trace.

[goroutine <n>] [frame <m>] stack [<depth>] [-full] [-offsets] [-defer] [-a <n>] [-adepth <depth>] [-mode <mode>]

-full		every stackframe is decorated with the value of its local variables and arguments.
-offsets	prints frame offset of each frame.
-defer		prints deferred function call stack for each frame.
-a <n>		prints stacktrace of n ancestors of the selected goroutine (target process must have tracebackancestors enabled)
-adepth <depth>	configures depth of ancestor stacktrace
-mode <mode>	specifies the stacktrace mode, possible values are:
		normal	- attempts to automatically switch between cgo frames and go frames
		simple	- disables automatic switch between cgo and go
		fromg	- starts from the registers stored in the runtime.g struct

Aliases: bt

step

Single step through program.

Aliases: s

step-instruction

Single step a single cpu instruction.

Aliases: si stepi

stepout

Step out of the current function.

Aliases: so

target

Manages child process debugging.

target follow-exec [-on [regex]] [-off]

Enables or disables follow exec mode. When follow exec mode Delve will automatically attach to new child processes executed by the target process. An optional regular expression can be passed to 'target follow-exec', only child processes with a command line matching the regular expression will be followed.

target list

List currently attached processes.

target switch [pid]

Switches to the specified process.

thread

Switch to the specified thread.

thread <id>

Aliases: tr

threads

Print out info for every traced thread.

toggle

Toggles on or off a breakpoint.

toggle <breakpoint name or id>

trace

Set tracepoint.

trace [name] [locspec]

A tracepoint is a breakpoint that does not stop the execution of the program, instead when the tracepoint is hit a notification is displayed. See Documentation/cli/locspec.md for the syntax of locspec. If locspec is omitted a tracepoint will be set on the current line.

See also: "help on", "help cond" and "help clear"

Aliases: t

transcript

Appends command output to a file.

transcript [-t] [-x] <output file>
transcript -off

Output of Delve's command is appended to the specified output file. If '-t' is specified and the output file exists it is truncated. If '-x' is specified output to stdout is suppressed instead.

Using the -off option disables the transcript.

types

Print list of types

types [<regex>]

If regex is specified only the types matching it will be returned.

up

Move the current frame up.

up [<m>]
up [<m>] <command>

Move the current frame up by <m>. The second form runs the command on the given frame.

vars

Print package variables.

vars [-v] [<regex>]

If regex is specified only package variables with a name matching it will be returned. If -v is specified more information about each package variable will be shown.

watch

Set watchpoint.

watch [-r|-w|-rw] <expr>

-r	stops when the memory location is read
-w	stops when the memory location is written
-rw	stops when the memory location is read or written

The memory location is specified with the same expression language used by 'print', for example:

watch v
watch -w *(*int)(0x1400007c018)

will watch the address of variable 'v' and writes to an int at addr '0x1400007c018'.

Note that writes that do not change the value of the watched memory address might not be reported.

See also: "help print".

whatis

Prints type of an expression.

whatis <expression>