Byebug
Byebug is a simple to use and feature rich debugger for Ruby. It uses the
TracePoint API for execution control and the Debug Inspector API for call stack
navigation. Therefore, Byebug doesn't depend on internal core sources. Byebug is also
fast because it is developed as a C extension and reliable because it is supported
by a full test suite.
The debugger permits the ability to understand what is going on inside a Ruby program
while it executes and offers many of the traditional debugging features such as:
- Stepping: Running your program one line at a time.
- Breaking: Pausing the program at some event or specified instruction, to
examine the current state. - Evaluating: Basic REPL functionality, although pry does a better job at
that. - Tracking: Keeping track of the different values of your variables or the
different lines executed by your program.
Build Status
Requirements
- Required: MRI 2.4.0 or higher.
- Recommended: MRI 2.6.4 or higher (MRI 2.6.0 to 2.6.3 contain a regression
causing unbalanced call/return events in some cases, breaking thenext
command).
Install
gem install byebug
Alternatively, if you use bundler
:
bundle add byebug --group "development, test"
Usage
From within the Ruby code
Simply include byebug
wherever you want to start debugging and the execution will
stop there. For example, if you were debugging Rails, you would add byebug
to
your code:
def index
byebug
@articles = Article.find_recent
end
And then start a Rails server:
bin/rails s
Once the execution gets to your byebug
command, you will receive a debugging prompt.
From the command line
If you want to debug a Ruby script without editing it, you can invoke byebug from the command line.
byebug myscript.rb
Byebug's commands
Command, Aliases, Subcommands
-------, -------, -----------
backtrace
, bt
w
where
, break
, b
, catch
, cat
, condition
, cond
, continue
, c
cont
, debug
, delete
, del
, disable
, dis
, breakpoints
display
display
, disp
, down
, edit
, ed
, enable
, en
, breakpoints
display
finish
, fin
, frame
, f
, help
, h
, history
, hist
, info
, i
, args
breakpoints
catch
display
file
line
program
interrupt
, int
, irb
, kill
, list
, l
, method
, m
, instance
next
, n
, pry
, quit
, q
, restart
, save
, sa
, set
, autoirb
autolist
autopry
autosave
basename
callstyle
fullpath
histfile
histsize
linetrace
listsize
post_mortem
savefile
stack_on_error
width
show
, autoirb
autolist
autopry
autosave
basename
callstyle
fullpath
histfile
histsize
linetrace
listsize
post_mortem
savefile
stack_on_error
width
skip
, sk
, source
, so
, step
, s
, thread
, th
, current
list
resume
stop
switch
tracevar
, tr
, undisplay
, undisp
, untracevar
, untr
, up
, var
, v
, all
constant
global
instance
local
Semantic Versioning
Byebug attempts to follow semantic versioning and
bump major version only when backwards incompatible changes are released.
Backwards compatibility is targeted to pry-byebug and any other plugins
relying on byebug
.
Getting Started
Read byebug's markdown
guide to get
started. Proper documentation will be eventually written.
Related projects
- pry-byebug adds
next
,step
,finish
,continue
andbreak
commands
topry
usingbyebug
. - ruby-debug-passenger adds a rake task that restarts Passenger with Byebug
connected. - minitest-byebug starts a byebug session on minitest failures.
- sublime_debugger provides a plugin for ruby debugging on Sublime Text.
- atom-byebug provides integration with the Atom editor [EXPERIMENTAL].
Contribute
See Getting Started with Development.
Funding
Subscribe to Tidelift to ensure byebug stays actively maintained, and at the
same time get licensing assurances and timely security notifications for your
open source dependencies.
You can also help byebug
by leaving a small (or big) tip through Liberapay.
Security contact information
Please use the Tidelift security contact to report a security vulnerability.
Tidelift will coordinate the fix and disclosure.
Credits
Everybody who has ever contributed to this forked and reforked piece of
software, especially: