Troubleshooting Tools

Troubleshooting any operating system can involve a whole suite of specialized software. However, sometimes you just need a quick tool to report specific aspects of your computer. Table A.11 contains some of these utilities found in Linux environments.

Table A.11. Common Troubleshooting Tools

COMMAND	GENERAL USAGE	DESCRIPTION
dmesg	dmesg	Displays the kernel ring buffer.
free	free	Displays the amount of free and used memory on the system.
hwinfo	hwinfo	Queries and displays detected hardware.
iostat	iostat [OPTIONS] INTERVAL COUNT	Displays CPU statistics and input/ output statistics on block devices (hard disks). Common options include -d Print device utilization -t Print time for each report -x Print extended statistics
lsof	lsof [OPTIONS]	Lists currently open files. Common options include -b Find open files on the specified filesystem mount point
ltrace	ltrace [OPTIONS] COMMAND	Traces library calls made by a process. Common options include -c Count time and calls, and return a summary upon completion -p Used to attach to a running process
sitar	sitar	Comprehensive reporting tool used to generate a report documenting the entire running environment. The report file can be located in the /tmp/sitar-<SERVER-NAME> directory.
strace	strace [OPTIONS] COMMAND	Traces system calls and signals made by a process. Common options include -c Count time and calls, and return a summary upon completion -p Used to attach to a running process
uname	uname [OPTIONS]	Displays kernel version information.
vmstat	vmstat	Displays virtual memory statistics.