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mcrmfc/ruby-debug cheat sheet

Created May 9, 2011 12:52
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ruby-debug cheat sheet
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ruby-debug cheat sheet
To end the debugging session and return control to the app:
quit
To find out where you are:
where
Note, this will print out a stack trace only if you’ve added the Debugger.start as specified above. If you haven’t, where will only print out the line number and file name of where execution has reached.
To see where you are in context (current line with a few lines before and after):
list
To print out the value of an individual variable:
p my_var
To print out all local and instance variables in the current stack frame:
info variables
To go to the next step (equivalent of ‘step into’):
step
To step over the next line:
next
To let the app run to the next breakpoint:
continue
To restart the app:
restart
@rocky
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rocky commented May 9, 2011

Many folks like "set autoeval on". In the newer *trepanning debuggers that is on by default. We don't change it for ruby-debug because of the confusion it might cause on entering an invalid command.

Anothre popular setting is "set different". When on, it causes stopping at a different line. Sometimes stepping is tedious without it. There are suffixes + and - to step and next which change this for the next command.

Another popular command is "irb" to go into an irb session.

You list "continue" to go to the next breakpoint (or debugger call), but nothing about setting breakpoints itself. And a popular option to "continue" is to give a line number which sets that line number as a temporary breakpoint. A temporary breakpoint is one which is removed as soon as it is hit. So, for example, "continue 8" would run until line 8.

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