Troubleshooting in Linux

 

Check your syslog for anything obvious (like most systems, linux is pretty good about mentioning in syslog what's wrong, its just a matter of finding it) If its difficult to find it, you can always clear the log and monitor.

 

dmidecode | less (shows everything in BIOS)

lscpu (lists available cpus)

lshal (list all hardware visible by HAL)

lspci (shows all PCI devices)

lsusb (shows all USB devices)

lsblk (shows all block devices like hardrives, cdroms)

lsmod (shows installed device drivers/modules)

df -h (disk space usage)

du -h (estimate disk usage)

cat /proc/partitions (show partitions)

grep processor /proc/cpuinfo | wc -l (If the load averages show that the load is increasing and is above the number of CPUs, you should look at what is causing the load. Load is a combined measure of CPU and I/O utilisation so top can be used to get real-time statistics.)

vmstat 5 10 (the free column shows that the amount of free memory, The si and so columns show the amount of data being transferred between the system’s swap and its memory)

 

route (shows network route)

netstat -tulpn (list of all open ports)

 

 

free -m (shows memory and swap information)

 

top (display list of tasks)

ps aux (display all running processes)

ps aux | grep process-name

rpm -qa (shows what software is installed)

 

ulimit -a (find out user limits)

ps -p $$ | tail -1 | awk '{ print $4 }'  (find out user shell)

tail -f /var/log/secure (view login logs)

vi /var/log/secure (view login logs)

grep 'something' /var/log/secure (view login logs)

who (whos logged on)