Is there a way to automatically start a process under gdb on Linux? An equivalent of setting the Image File Execution Options on Windows.
I am trying to debug start-up phase of a process that is launched from another one.
I would normally move the real program out of the way, and replace it with a script that launches the program under GDB with the same parameters.
#!/bin/bash
exec gdb -args <realprog> "$#"
If that doesn't work due to the output being redirected to file, or something, then try this:
#!/bin/bash
exec xterm -e gdb -args <realprog> "$#"
That should give you a pop-up terminal with GDB running inside.
You don't have to go through all that registry voodoo on Linux :)
Simply:
1) Rename your program
2) Write a shell script that calls gdb with your (renamed) program and passes any arguments you want. Make sure you "chmod +rx" your script.
3) Name the shell script the original name of your program, and put it in the same directory as your program
4) Execute!
Related
I've found a very strange issue, when in linux terminal I type "enable -n trap", it would disable the trap linux builtin command. But if I put it into a script like
#!/bin/bash
enable -n trap
and then run the script, there's no error but the command is also not disabled. Really appreciate if someone could share what is happening and how to run it in some file instead of directly in the terminal. Thank you!
The enable command only affects the current shell. When you run a script, that script is executed in a new process, so:
A new shell starts
The enable command runs and disables the trap command in that shell
The shell exits
If you want to affect the current shell, your only option is to source the script using the . (or source) command. If the script is named disable-trap.sh and is in your $PATH, you can run:
. disable-trap.sh
You can also provide a full path to the script:
. /path/to/disable-trap.sh
Sourcing a script like this is largely equivalent to typing the same commands in at the command line: it executes the instructions in the script in the current shell, rather than spawning a new process.
My intentions are the following. I am debugging an object file compiled with gcc from a .c script. Lets call this compiled script "foo". When I run the command from my terminal on mac:
gdb -q ./foo
I get the an output of:
Reading symbols from ./foo...Reading symbols from /Users/john/Documents....done.
done.
And immediately I get a prompt from the shell looking like so:
(gdb) "Shell waiting for my input command here from keyboard"
At this point I want to automate the input of certain commands like:
break, list, x/x "symbol in .c file", x/s "symbol in .c file" and many more. For this automation I want to use a little bash script, and so far I have the following:
#!/bin/bash
SCRIPT=$1
gstdbuf -oL gdb -q $SCRIPT |
while read -r LINE
do
echo "$LINE"
done
At the point of executing this bash script, I see the following output on my terminal's shell:
Reading symbols from ./foo...Reading symbols from /Users/john/Documents....done.
done.
But I do not see the:
(gdb) "Shell waiting for my input command here from keyboard"
How can I detect this prompt from the gdb process in my shell script in order to be able to automate the commands I want instead of inputting them manually?
Many Thanks!
You can create a file .gdbinit and put the initial commands there. gdb will execute them on startup if you added the following line to $HOME/.gdbinit:
add-auto-load-safe-path /path/to/project/.gdbinit
Now you can place commands into /path/to/project/.gdbinit, like this:
break main
run --foo=bar
I am creating a terminal program and cannot find out what the ending is for Linux. I know in windows it is .cmd. Any help would be great.
Thank you.
Yes, you can remove the .sh at the end and it should work, generally using ./cmd will get it to run. this goes for C programs as well. You do not need to give an extension for the object file, You could then add a path to your bash file and then you can execute it as a normal command.
Look here.
https://stackoverflow.com/a/8779980/2720497
You don't need a file extension on Linux, though typically, people use .sh (sh being short for 'shell').
You can run it one of two ways:
bash myscript.sh
or you can make the script itself executable and run it directly:
chmod a+x myscript.sh # make it executable
./myscript.sh # run it
Linux scripts' first line is typically #!/bin/bash which is the path to the specific shell used to run the script with the second method.
Is there a command line utility that I can use for executing X based applications that will detach my applications from the terminal so they aren't closed if the terminal is closed?
I guess such a app could be called something like gnome-run if it existed.
I have tried dtach, but it seems that you have to provide a socket file which is a bit clunky to type. I have also tried nohup, but found that also to be a bit clunky to type by the time std out and err are redirected to /dev/null.
I guess I'm looking for a simple program that will do something similar to this:
#!/bin/bash
nohup $1 > /dev/null 2>&1 &
Yes, there is a way to do it: first you need to run your GUI app and send it to background, then you (probably) want to detach it from Bash task management. For example if I wanted to run gedit this way:
gedit &
disown %1
After that you can close your terminal window and gedit will not be killed. Enjoy!
You already wrote your program, it is called a shell script and you give it the name you like and put it somewhere. Then you either add that directory to your $PATH or in your bashrc you set:
alias gnome-run=<path>/my-awesome-script.sh
Why waste earth's resources on a program?
If you want to run an application (say, gedit) as if it was run from the GUI, use:
xdg-open /usr/share/applications/gedit.desktop
See this answer on superuser.
I have a zsh script that I want to run such that it also loads up my .zshrc file.
I believe I have to run my script in interactive mode?
Thus, my script begins like:
#!/bin/zsh -i
if [ $# = 0 ]
then
echo "need command line paramter..."
exit
fi
However, when I try to run this script in the background, my script becomes suspended (even if I pass in the correct number of parameters):
[1] + suspended (tty output)
My question is: How can I make a script that can run in the background that also loads my startup .zshrc file? If I have to put it into interactive mode, how can I avoid the suspension on tty output problem?
Thanks
Don't use interactive mode as a hash-bang!
Instead, source your zshrc file in the script if you want it:
#!/bin/zsh
source ~/.zshrc
...
For future reference, you can use the disown bultin to detach a previously backgrounded job from the shell so it can't be suspended or anything else. The parent shell can then be closed with no affect on the process:
$ disown %1
You can do this directly from the command line when you start the program by using the &! operator instead of just &:
$ ./my_command &!