如果从脚本运行应用程序，则在 linux 中使用 GDB

Question

Normally we run gdb with gdb command and our application name. But if we want to run our application from a script eg my_script.sh as./my_script.sh argument and this starts our application. Then how to use gdb without including any command in script.

I want something like this: gdb./my_script.sh argument. So that whatever application will be started from script I can debug it.

Answer 1

Normally we run gdb with gdb command and our application name.

This is wrong . You use gdb on some binary executable file (in ELF format) or (with -p ) on a running process . For example, you cannot run gdb cd but cd is a shell builtin command (see also this ). BTW an executable file can have several names (eg /bin/rbash is a symbolic link to /bin/bash on my Debian computer), and programs can be started without being "applications" on your desktop menu. For example, my g++ executable would run /usr/lib/gcc/x86_64-linux-gnu/9/cc1plus . Check with strace(1) or by diving into the source code of GCC , or simply adding -v inside your g++ command.

Read documentation of GDB

and the gdb(1) and gdbserver(1) man page. Run also in a terminal gdb --help to understand how you could start it.

You might start (or improve your my_script.sh shell script to run) your ELF executable yourprog (obtained by compiling your C++ code) using

 gdb --args yourprog arg1toit arg2toit

and you could even use some pipeline (see pipe(7) or even unix(7) sockets) to pour commands into it. Of course yourprog should be compiled with g++ -Wall -g and perhaps also -O (assuming a recent enough GCC ).

In addition, recent GDB can be scripted or extended in Python or in Guile . You might need to compile and configure GDB from its source code , which you are allowed to do since it is free software .

If you need to debug a bash shell script, consider using bashdb , a shell script debugger . Of course spend an hour in reading its documentation. But if you want to debug a script coded in bash , why is your question tagged C++?

Read alsoHow to debug small programs

However, a process won't be able to debug directly itself without precautions. See ptrace(2) for details.

I want something like this: gdb./my_script.sh argument.

This is not possible.

GDB can (on recent Linux distributions) only debug an ELF executable (but not a shell script), preferably with DWARF debug information. Design your my_script.sh to sometimes run gdb . That debugged executable would be often compiled with GCC or Clang compilers (and -g options) from some C++ or C source code. You could find other compilers ( Ocaml , Rust , Go , ...) capable (with care) to produce ELF executables with DWARF debug information.

If your my_script.sh is written for GNU bash (so starts with #!/bin/bash , see execve(2) for details), read the documentation of GNU bash . You might consider rewriting your script in Python or in Guile or in Lua , since all these scripting languages are more expressive than POSIX shells. In all cases, read the documentation of the scripting language you have chosen to use . Most of them have debugging facilities. (you could replace #!/bin/bash with a line like #!/bin/bash -vx as the first line of your shell script).

NB. Notice that /usr/bin/firefox is often a script starting some /usr/bin/firefox.real ELF executable. You could glance inside it for inspiration.