Checking Linux System Information

Here are a number of example commands to check various points of a Linux system, disk, swap, memory, CPU, network and other system information. This covers basic hardware and core system commands. This is considered fundamental knowledge for any Linux System Administrator

CPU Information

This is all contained in /proc/cpuinfo which can be viewed with

cat /proc/cpuinfo
Check Number of Cores
egrep '^processor' /proc/cpuinfo
Check Processor for 64bit
grep ' lm ' /proc/cpuinfo
Check for Virtualization
egrep '^flags.*(vmx|svm)' /proc/cpuinfo

Memory Information

Kernel Memory Details
cat /proc/meminfo
System Memory Details
free -m
Swap Information
cat /proc/swaps
Also /etc/fstab

Disk Information

Disks List
Use one of the following
ls /sys/block
ld /dev/sd*
dmesg |grep disk
Mounted Disk Space / Size
Most commonly using df -h.
df -h
Filesystem       Size  Used Avail Use% Mounted on
rootfs           145G  109G   29G  79% /
/dev/root        145G  109G   29G  79% /
devtmpfs         2.0G  240K  2.0G   1% /dev
rc-svcdir        1.0M   92K  932K   9% /lib64/rc/init.d
shm              2.0G  3.7M  2.0G   1% /dev/shm
tmpfs            2.0G     0  2.0G   0% /lib64/firmware
c:raid           917G  725G  146G  84% /mnt/raid

Kernel Information

uname -a
find /boot/
cat /boot/syslinux.cfg
cat /boot/grub/menu.lst

Network Information

Devices have names like eth0, wlan0, ath0, br0

netstat -tanpu
cat /etc/resolv.conf
cat /etc/conf.d/net
cat /etc/conf.d/hostname
cat /etc/hostname
cat /etc/network/*