man gdb Command

Man page for apt-get gdb Command

Man Page for gdb in Linux

This tutorial shows the man page for man gdb in linux.

Open terminal with 'su' access and type the command as shown below:
man gdb

Result of the Command Execution shown below:

gdb(1)                                                                        GNU Tools                                                                       gdb(1)



NAME
       gdb   The GNU Debugger

SYNOPSIS
       gdb    [ help] [ nx] [ q] [ batch] [ cd=dir] [ f] [ b bps] [ tty=dev] [ s symfile] [ e prog] [ se prog] [ c core] [ x cmds] [ d dir] [prog [core|procID]]

       gdb    [options]   args prog [arguments]

       gdbtui [options]

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 Äîor 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++, and Modula 2.  Fortran support will be added when a GNU Fortran compiler is ready.

       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.   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 argu Äê
       ment:

       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, if you want to debug a running process:

       gdb program 1234


       would attach GDB to process 1234 (unless you also have a file named `1234'; GDB does check for a core file first).

       Here are some of the most frequently needed GDB commands:

       break [file:]function
               Set a breakpoint at function (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 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
       short  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.
       (If you prefer, you can flag option arguments with `+' rather than ` ', though we illustrate the more usual convention.)

       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.

        b bps  Set the line speed (baud rate or bits per second) of any serial interface used by GDB for remote debugging.


        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 use Äê
              ful, 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.


        c FILE,  core=FILE
              Use file file as a core dump to examine.


        cd=directory
               Run GDB using directory as its working directory, instead of the current directory.


        d DIRECTORY,  directory=DIRECTORY
              Add directory to the path to search for source files.


        e FILE,  exec=FILE
              Use file file as the executable file to execute when appropriate, and for examining pure data in conjunction with a core dump.


        f,  fullname
              Emacs sets this option when it runs GDB as a subprocess.  It tells GDB to output the full file name and line number in a standard, recognizable  fash Äê
              ion each time a stack frame is displayed (which includes each time the program stops).  This recognizable format looks like two ` 32' characters, fol Äê
              lowed by the file name, line number and character position separated by colons, and a newline.  The Emacs to GDB interface program uses the two  ` 32'
              characters as a signal to display the source code for the frame.


        h,  help
              List all options, with brief explanations.


        n,  nx
              Do  not  execute  commands from any `.gdbinit' initialization files.  Normally, the commands in these files are executed after all the command options
              and arguments have been processed.


        s FILE,  symbols=FILE
              Read symbol table from file file.


        se=file
              Read symbol table from file file and use it as the executable file.


       q,  quiet
              ``Quiet''.  Do not print the introductory and copyright messages.  These messages are also suppressed in batch mode.


        tty=device
               Run using device for your program's standard input and output.


         args Pass arguments after the program name to the program when it is run.


        tui   Run GDB using a text (console) user interface.

        write Enable writing into executable and core files.


        x FILE,  command=FILE
              Execute GDB commands from file file.

SEE ALSO
       `gdb' entry in info; Using GDB: A Guide to the GNU Source Level Debugger, Richard M. Stallman and Roland H. Pesch, July 1991.

COPYING
       Copyright (c) 1991, 2010 Free Software Foundation, Inc.

       Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice  are  preserved  on  all
       copies.

       Permission  is  granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting
       derived work is distributed under the terms of a permission notice identical to this one.

       Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that
       this permission notice may be included in translations approved by the Free Software Foundation instead of in the original English.



GNU Tools                                                                     22may2002                                                                       gdb(1)-

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