# man > GDB(1) > **TLDR:** The GNU Debugger. > - Debug an executable: `gdb {{path/to/executable}}` - Attach a process to `gdb`: `gdb {{-p|--pid}} {{process_id}}` - Debug with a core file: `gdb {{-c|--core}} {{path/to/core}} {{path/to/executable}}` - Execute given GDB commands upon start: `gdb {{-ex|--eval-command}} "{{commands}}" {{path/to/executable}}` - Start `gdb` and pass arguments to the executable: `gdb --args {{path/to/executable}} {{argument1 argument2 ...}}` - Skip `debuginfod` and pagination prompts and then print the backtrace: `gdb {{-c|--core}} {{path/to/core}} {{path/to/executable}} -iex 'set debuginfod enabled on' -iex 'set pagination off' -ex bt` *Source: tldr-pages* --- [GDB(1)](https://www.chedong.com/phpMan.php/man/GDB/1/markdown) GNU Development Tools [GDB(1)](https://www.chedong.com/phpMan.php/man/GDB/1/markdown) ## NAME gdb - The GNU Debugger ## SYNOPSIS gdb [OPTIONS] [_prog_|_prog_ _procID_|_prog_ _core_] ## DESCRIPTION The purpose of a debugger such as GDB is to allow you to see what is going on "inside" another program while it executes -- or what another program was doing at the moment it crashed. GDB can do four main kinds of things (plus other things in support of these) to help you catch bugs in the act: • Start your program, specifying anything that might affect its behavior. • Make your program stop on specified conditions. • Examine what has happened, when your program has stopped. • Change things in your program, so you can experiment with correcting the effects of one bug and go on to learn about another. You can use GDB to debug programs written in C, C++, Fortran and Modula-2. GDB is invoked with the shell command "gdb". Once started, it reads commands from the terminal until you tell it to exit with the GDB command "quit" or "exit". You can get online help from GDB itself by using the command "help". You can run "gdb" with no arguments or options; but the most usual way to start GDB is with one argument or two, specifying an executable program as the argument: gdb program You can also start with both an executable program and a core file specified: gdb program core You can, instead, specify a process ID as a second argument or use option "-p", if you want to debug a running process: gdb program 1234 gdb -p 1234 would attach GDB to process 1234. With option **-p** you can omit the _program_ filename. Here are some of the most frequently needed GDB commands: **break** **[**_file_**:][**_function_**|**_line_**]** Set a breakpoint at _function_ or _line_ (in _file_). **run** **[**_arglist_**]** Start your program (with _arglist_, if specified). **bt** Backtrace: display the program stack. **print** _expr_ Display the value of an expression. **c** Continue running your program (after stopping, e.g. at a breakpoint). ### next Execute next program line (after stopping); step _over_ any function calls in the line. **edit** **[**_file_**:]**_function_ look at the program line where it is presently stopped. **list** **[**_file_**:]**_function_ type the text of the program in the vicinity of where it is presently stopped. ### step Execute next program line (after stopping); step _into_ any function calls in the line. **help** **[**_name_**]** Show information about GDB command _name_, or general information about using GDB. ### quit ### exit Exit from GDB. For full details on GDB, see _Using_ _GDB:_ _A_ _Guide_ _to_ _the_ _GNU_ _Source-Level_ _Debugger_, by Richard M. Stallman and Roland H. Pesch. The same text is available online as the "gdb" entry in the "info" program. ## OPTIONS Any arguments other than options specify an executable file and core file (or process ID); that is, the first argument encountered with no associated option flag is equivalent to a **--se** option, and the second, if any, is equivalent to a **-c** option if it's the name of a file. Many options have both long and abbreviated forms; both are shown here. The long forms are also recognized if you truncate them, so long as enough of the option is present to be unambiguous. The abbreviated forms are shown here with **-** and long forms are shown with **--** to reflect how they are shown in **--help**. However, GDB recognizes all of the following conventions for most options: "--option=_value_" "--option _value_" "-option=_value_" "-option _value_" "--o=_value_" "--o _value_" "-o=_value_" "-o _value_" All the options and command line arguments you give are processed in sequential order. The order makes a difference when the **-x** option is used. ### --help ### -h **--symbols=**_file_ ### -s Read symbol table from _file_. ### --write Enable writing into executable and core files. **--exec=**_file_ ### -e Use _file_ as the executable file to execute when appropriate, and for examining pure data in conjunction with a core dump. **--se=**_file_ Read symbol table from _file_ and use it as the executable file. **--core=**_file_ ### -c Use _file_ as a core dump to examine. **--command=**_file_ ### -x Execute GDB commands from _file_. **--eval-command=**_command_ ### -ex Execute given GDB _command_. **--init-eval-command=**_command_ ### -iex Execute GDB _command_ before loading the inferior. **--directory=**_directory_ ### -d Add _directory_ to the path to search for source files. ### --nh Do not execute commands from _~/.config/gdb/gdbinit_, _~/.gdbinit_, _~/.config/gdb/gdbearlyinit_, or _~/.gdbearlyinit_ ### --nx ### -n ### --quiet ### --silent ### -q suppressed in batch mode. ### --batch Run in batch mode. Exit with status 0 after processing all the command files specified with **-x** (and _.gdbinit_, if not inhibited). Exit with nonzero status if an error occurs in executing the GDB commands in the command files. Batch mode may be useful for running GDB as a filter, for example to download and run a program on another computer; in order to make this more useful, the message Program exited normally. (which is ordinarily issued whenever a program running under GDB control terminates) is not issued when running in batch mode. ### --batch-silent Run in batch mode, just like **--batch**, but totally silent. All GDB output is supressed (stderr is unaffected). This is much quieter than **--silent** and would be useless for an interactive session. This is particularly useful when using targets that give **Loading** **section** messages, for example. Note that targets that give their output via GDB, as opposed to writing directly to "stdout", will also be made silent. **--args** _prog_ **[**_arglist_**]** Change interpretation of command line so that arguments following this option are passed as arguments to the inferior. As an example, take the following command: gdb ./a.out -q It would start GDB with **-q**, not printing the introductory message. On the other hand, using: gdb --args ./a.out -q starts GDB with the introductory message, and passes the option to the inferior. **--pid=**_pid_ Attach GDB to an already running program, with the PID _pid_. ### --tui Open the terminal user interface. ### --readnow Read all symbols from the given symfile on the first access. ### --readnever Do not read symbol files. ### --dbx Run in DBX compatibility mode. ### --return-child-result GDB's exit code will be the same as the child's exit code. ### --configuration Print details about GDB configuration and then exit. ### --version Print version information and then exit. **--cd=**_directory_ Run GDB using _directory_ as its working directory, instead of the current directory. **--data-directory=**_directory_ ### -D for its auxiliary files. ### --fullname ### -f file name and line number in a standard, recognizable fashion each time a stack frame is displayed (which includes each time the program stops). This recognizable format looks like two **\032** characters, followed by the file name, line number and character position separated by colons, and a newline. The Emacs-to-GDB interface program uses the two **\032** characters as a signal to display the source code for the frame. ### -b Set the line speed (baud rate or bits per second) of any serial interface used by GDB for remote debugging. ### -l Set timeout, in seconds, for remote debugging. **--tty=**_device_ Run using _device_ for your program's standard input and output. ## SEE ALSO The full documentation for GDB is maintained as a Texinfo manual. If the "info" and "gdb" programs and GDB's Texinfo documentation are properly installed at your site, the command info gdb should give you access to the complete manual. _Using_ _GDB:_ _A_ _Guide_ _to_ _the_ _GNU_ _Source-Level_ _Debugger_, Richard M. Stallman and Roland H. Pesch, July 1991. ## COPYRIGHT Copyright (c) 1988-2022 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being "Free Software" and "Free Software Needs Free Documentation", with the Front-Cover Texts being "A GNU Manual," and with the Back-Cover Texts as in (a) below. (a) The FSF's Back-Cover Text is: "You are free to copy and modify this GNU Manual. Buying copies from GNU Press supports the FSF in developing GNU and promoting software freedom." gdb- 2024-06-13 [GDB(1)](https://www.chedong.com/phpMan.php/man/GDB/1/markdown)