What tools are used for diagnosing and troubleshooting in Linux systems?

Tools commonly used for diagnosing and troubleshooting issues in Linux include:

• top, htop — monitoring processes and system load in real-time.
• ps — viewing running processes.
• dmesg — viewing kernel system messages, useful for hardware problem diagnosis.
• journalctl — viewing systemd logs.
• strace — tracing system calls of a process, helps understand what the program is doing.
• lsof — shows open files and ports.
• netstat, ss — diagnosing network connections.
• vmstat, iostat — monitoring CPU, memory, and disk resources.
• tcpdump — capturing and analyzing network traffic.
• gdb — debugger for programs.

Example of using strace for diagnosis:

strace -p <pid>

This allows you to see the system calls of the process with the specified pid.