Monitoring and system information under Linux

tail –f /var/log/messages
strace -c ls >/dev/null Summarise/profile system calls made by command
lsof -p $$ List paths that process id has open
lsof ~ List processes that have specified path open
tcpdump not port 22
watch -n.1 'cat /proc/interrupts' Watch changeable data continuously
free –m Show amount of (remaining) RAM (-m displays in MB)

ps -e -orss=,args= | sort -b -k1,1n | pr -TW$COLUMNS
List processes by mem usage
ps -e -o pcpu,cpu,nice,state,cputime,args --sort pcpu | sed '/^ 0.0 /d'
List processes by % cpu usage
ps -e -o pid,args –forest List processes in a hierarchy

uname –a
badblocks -s /dev/sda
hdparm -tT /dev/sda Do a read speed test on disk sda
hdparm -i /dev/sda Show info about disk sda
smartctl -A /dev/sda | grep Power_On_Hours How long has this disk (system) been powered on in total
mount | column –t List mounted filesystems on the system (and align output)
lsusb –tv Show USB info
grep "model name" /proc/cpuinfo Show CPU(s) info
grep MemTotal /proc/meminfo Show RAM total seen by the system