debugging - gdb command scripts - Multiple commands in gdb separated by some sort of delimiter ';'?


2 Answers

If you are running gdb from command line you can pass multiple commands with the -ex parameter like:

$ gdb ./prog -ex 'b srcfile.c:90' -ex 'b somefunc' -ex 'r -p arg1 -q arg2'

This coupled with display and other commands makes running gdb less cumbersome.

Question

gdb command source

I am trying to execute two commands at once in gdb:

finish; next

I tried using the ';' to separate the commands but gdb did not let me do both at once.

Is it possible to do multiple commands in gdb similar to bash commands separated by ';' delimiter?




You can do this using the python integration in gdb.

It would be nice if s ; bt stepped and then printed a backtrace, but it doesn't.

You can accomplish the same thing by calling into the Python interpreter.

python import gdb ; print gdb.execute("s") ; print gdb.execute("bt")

It's possible to wrap this up into a dedicated command, here called "cmds", backed by a python definition.

Here's an example .gdbinit extended with a function to run multiple commands.

# multiple commands
python
import gdb


class Cmds(gdb.Command):
  """run multiple commands separated by ';'"""
  def __init__(self):
    gdb.Command.__init__(
      self,
      "cmds",
      gdb.COMMAND_DATA,
      gdb.COMPLETE_SYMBOL,
      True,
    )

  def invoke(self, arg, from_tty):
    for fragment in arg.split(';'):
      # from_tty is true. These commands should be considered interactive.
      # to_string is false. We just want to write the output of the commands, not capture it.
      gdb.execute(fragment, from_tty=True, to_string=False)
      print


Cmds()
end

example invocation:

$ gdb
(gdb) cmds echo hi ; echo bye
hi
bye



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