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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.

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4 Answers 4

Reset to default
30

(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.

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3 Comments

is there a way to use the output of the shell command in a gdb command without copying? attach shell ps -C <program_name> doesn't seem to work for me, so I can only do shell ps -C <program_name> <copy the output> attach <paste> but it would be great if there was a better option
in my case I need to shell to a ssh command to get the .text address of a kernel module so I can tell the local gdb to load symbols for that address, being able to take the result of a script and run it as a gdb command would make this super easy.
2021 and looking for the same. I'd be happy enough if I could display the output of a shell-command called in a "define".
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gdb$ shell

shell$ execute_your_commands 

shell$ exit

gdb$ you_have_returned_back_to_gdb_prompt
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16

You can just use shell followed by the command you want to execute, e.g.:

gdb$ shell g++ tsort.c -o tsort

This is just a short form of the previous answer.

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1 Comment

In this mode gdb does not seem to pick up or be able to report problems when there is core dump.
8

Just to expand on the accepted answer, the shortcut for shell is !.

(gdb) help !

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

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