Byebug
Byebug is a simple to use, feature rich debugger for Ruby. It uses the TracePoint API for execution control and the Debug Inspector API for call stack navigation, so it doesn't depend on internal core sources. It's developed as a C extension, so it's fast. And it has a full test suite so it's reliable.
It allows you to see 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 2.2.0 or higher.
-
Recommended: MRI 2.3.0 or higher.
Install
gem install byebug
Or if you use bundler
,
bundle add byebug --group "development, test"
Usage
From within the Ruby code
Simply drop byebug
wherever you want to start debugging and the execution will
stop there. If you were debugging Rails, for example, 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 get 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 where |
|
break |
||
catch |
||
condition |
||
continue |
||
debug |
||
delete |
||
disable |
breakpoints display |
|
display |
||
down |
||
edit |
||
enable |
breakpoints display |
|
finish |
||
frame |
||
help |
||
history |
||
info |
args breakpoints catch display file line program |
|
interrupt |
||
irb |
||
kill |
||
list |
||
method |
instance |
|
next |
||
pry |
||
quit |
||
restart |
||
save |
||
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 |
|
source |
||
step |
||
thread |
current list resume stop switch |
|
tracevar |
||
undisplay |
||
untracevar |
||
up |
||
var |
all constant global instance local |
Semantic Versioning
Byebug tries to follow semantic versioning and tries to
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.
You can also help byebug
by leaving a small (or big) tip through
Liberapay.
Credits
Everybody who has ever contributed to this forked and reforked piece of software, especially: