gdb command in Linux
The gdb command in Linux is a powerful tool for debugging programs. It allows developers to inspect and manipulate the execution of their code, set breakpoints, and analyze memory usage. With gdb, users can trace the flow of their program, step through code line by line, and identify errors in their logic. This command also provides advanced features for analyzing and troubleshooting code effectively, making it an essential tool for software developers working on Linux systems.
gdb Syntax:
Section titled “gdb Syntax:”gdb [options] [executable_file [core_file or process_id]]Linux gdb Options:
Section titled “Linux gdb Options:”| Option | Description |
|---|---|
| -c <file> | Use a core dump file for debugging |
| -e <file> | Use an executable file for debugging |
| -q | Don’t print version message on startup |
| -x <file> | Read and execute commands from a file |
| -pid <number> | Attach to a running process by process ID |
| -s <file> | Use a command script provided in a file |
| -batch | Run in batch mode |
| -cd <directory> | Run in the specified directory |
| -n | Initiate without reading init file |
gdb Parameters:
Section titled “gdb Parameters:”| Parameter | Description |
|---|---|
| executable_file | The executable file to be debugged |
| core_file | The core dump file for debugging (if applicable) |
| process_id | The Process ID of a running process to attach to |
How to use gdb command:
Section titled “How to use gdb command:”Run a Program in gdb
Section titled “Run a Program in gdb”gdb ./my_programRun a program called “my_program” within gdb to start the debugging session.
Set a Breakpoint
Section titled “Set a Breakpoint”break mainSet a breakpoint at the beginning of the main function in the program being debugged.
List Source Code
Section titled “List Source Code”listDisplay the source code around the current point of execution within gdb.
Display Variable Value
Section titled “Display Variable Value”p my_variablePrint the current value of a variable named “my_variable” during debugging.
Step Through Code
Section titled “Step Through Code”nextExecute the next line of code within gdb, stepping over function calls.
Step Into Function
Section titled “Step Into Function”stepExecute the next line of code within gdb, stepping into functions if applicable.
Continue Execution
Section titled “Continue Execution”continueContinue the execution of the program until the next breakpoint is encountered or the program completes.
Examine Memory
Section titled “Examine Memory”x/10x 0x7fffffffeff8Display the hexadecimal values of 10 memory locations starting from the specified address within gdb.
How do I run gdb in Linux?
Section titled “How do I run gdb in Linux?”To run the gdb command in Linux, use the following syntax:
gdb <program_name>How can I set breakpoints in gdb?
Section titled “How can I set breakpoints in gdb?”To set breakpoints in gdb, use the following command:
break <line_number>How do I start gdb with a specific program?
Section titled “How do I start gdb with a specific program?”To start gdb with a specific program, use the following command:
gdb -exec <program_name>How can I display the source code in gdb?
Section titled “How can I display the source code in gdb?”To display the source code in gdb, use the following command:
listHow do I continue execution in gdb?
Section titled “How do I continue execution in gdb?”To continue execution in gdb, use the following command:
continueHow can I examine variables in gdb?
Section titled “How can I examine variables in gdb?”To examine variables in gdb, use the following command:
print <variable_name>How do I step through code in gdb?
Section titled “How do I step through code in gdb?”To step through code in gdb, use the following command:
stepHow can I quit gdb?
Section titled “How can I quit gdb?”To quit gdb, use the following command:
quitHow do I enable verbose mode in gdb?
Section titled “How do I enable verbose mode in gdb?”To enable verbose mode in gdb, use the following command:
set verbose onApplications of the gdb command
Section titled “Applications of the gdb command”- Debugging programs
- Analyzing memory usage
- Inspection and modification of program variables
- Backtracing function calls
- Catching and handling signals
- Examining registers and memory contents
- Setting breakpoints
- Stepping through code
- Viewing disassembled code