How do I run a program with commandline arguments using GDB within a Bash script?

Question

When running a program on GDB, usually, the arguments for the program are given at the run command. Is there a way to run the program using GDB and as well as give arguments within a shell script?

I saw an answer in a related question, mentioning that we can attach GDB to the program after the script starts executing. But then I will have to 'wait' the program.

Is there another way to do this?

Answer 1

gdb -ex=r --args myprogram arg1 arg2

-ex=r is short for -ex=run and tells gdb to run your program immediately, rather than wait for you to type "run" at the prompt. Then --args says that everything that follows is the command and arguments, just as you'd normally type them at the commandline prompt.

Answer 2

Another way to do this, which I personally find slightly more convenient and intuitive (without having to remember the --args parameter), is to compile normally, and use r arg1 arg2 arg3 directly from within gdb, like so:

$ gcc -g *.c *.h
$ gdb ./a.out
(gdb) r arg1 arg2 arg3

Answer 3

You could create a file with context:

run arg1 arg2 arg3 etc

program input

And call gdb like

gdb prog < file

Answer 4

Much too late, but here is a method that works during gdb session.

gdb <executable>

then

(gdb) apropos argument

This will return lots of matches, the useful one is set args.

set args -- Set argument list to give program being debugged when it is started.

set args arg1 arg2 ...

then

r

This will run the program, passing to main(argc, argv) the arguments and the argument count.

Answer 5

If the --args parameter is not working on your machine (i.e. on Solaris 8), you may start gdb like

gdb -ex "set args <arg 1> <arg 2> ... <arg n>"

And you can combine this with inputting a file to stdin and "running immediatelly":

gdb -ex "set args <arg 1> <arg 2> ... <arg n> < <input file>" -ex "r"

Answer 6

In addition to the answer of Hugo Ideler. When using arguments having themself prefix like -- or -, I was not sure to conflict with gdb one.

It seems gdb takes all after args option as arguments for the program.

At first I wanted to be sure, I ran gdb with quotes around your args, it is removed at launch.

This works too, but optional:

gdb --args executablename "--arg1" "--arg2" "--arg3"

This doesn't work :

gdb --args executablename "--arg1" "--arg2" "--arg3" -tui

In that case, -tui is used as my program parameter not as gdb one.

Answer 7

gdb has --init-command <somefile> where somefile has a list of gdb commands to run, I use this to have //GDB comments in my code, then `

echo "file ./a.out" > run
grep -nrIH "//GDB"|
    sed "s/\(^[^:]\+:[^:]\+\):.*$/\1/g" |
    awk '{print "b" " " $1}'|
    grep -v $(echo $0|sed "s/.*\///g") >> run
gdb --init-command ./run -ex=r

as a script, which puts the command to load the debug symbols, and then generates a list of break commands to put a break point for each //GDB comment, and starts it running

Answer 8

If you want to pass arguments from file,
e.g. scanf from a file as input

try this

(gdb) run < the_file_contains_data