How to execute external commands from the gdb command prompt

gdb

I am debugging a program using gdb. Whenever I miss a breakpoint or decide to add another watchpoint, I have to kill the process and rerun it. In order to attach the existing gdb to it, I use attach <pid>. However, I have to find out the pid of the new process.

The way I do that today is to suspend gdb, get the pid with ps -C <program_name> and then return to gdb to attach to it.

Is there any way to run a unix command from the gdb command prompt without exiting to the shell, so that I could do something like this from inside gdb:

attach `ps -C <program_name>`

I am working on linux.

Best Answer

(gdb) help shell
Execute the rest of the line as a shell command. With no arguments, run an inferior shell.

After finish, you can use 'exit' to return to gdb.

Related Solutions

C++ – How to set breakpoints on future shared libraries with a command flag

Replying to myself, I'd like to give the answer that someone gave me on IRC:

(gdb) apropos pending
actions -- Specify the actions to be taken at a tracepoint
set breakpoint -- Breakpoint specific settings
set breakpoint pending -- Set debugger's behavior regarding pending breakpoints
show breakpoint -- Breakpoint specific settings
show breakpoint pending -- Show debugger's behavior regarding pending breakpoints

And so set breakpoint pending on does the trick; it is used in cmds.gdb like e.g.

set breakpoint pending on
break <source file name>:<line number>

How to continue to operate the gdb command console

Make sure the console which gdb is running in has keyboard focus, then press CTRL-C. This will usually result in a SIGINT signal to be sent to gdb. With me, GDB then pauses execution of the program and accepts user commands again.

Should the CTRL-C not work (perhaps different config) try to send the signal manually: Find out the pid of gdb such as with command top and then send a SIGINT to gdb:

kill -2 pidhere

Best Answer

Related Solutions

C++ – How to set breakpoints on future shared libraries with a command flag

How to continue to operate the gdb command console

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