This post will look at some common components that relate to device management under CentOS and other commonly used distro's.
procfs
procfs (/proc) contains a series of files that describe the kernel's current view of the system (for example cpu information) - allowing applications and users to retrieve information about the system.
Files within the proc directory are not standard text or binary files - rather they are referred to as 'virtual files' (this is because they are continually updated) and you will also notice that the file size of them is 0 bytes even though there is sometimes a large amount of information within them.
The majority of files are read-only - although there are some files that can be manually edited - for example /proc/sys/net/ipv4/ip_forward - which allows you to turn on IP forwarding - although changes made here will not persist a reboot and you will need to use something like sysctl to ensure the change is applied after reboots.
sysfs
The sys filesystem (/sys) is a combination of the proc, devfs, and devpty file systems that provides users with a hierarchy that enumerates devices and busses attached to the system. It can make identifying hardware components quicker than simply looking in the devfs.
udev
udev is a component that is used to dynamically create (and remove) files within the devfs (/dev) upon boot and also any hotpluggable devices. It also provides the ability of change block device names - for example when you would like to change an interface name.
lsusb
lsusb is a utility that allows us to quickly get an overview of all usb devices connected to the system - we can also get more detailed information by running:
lsusb -v /dev/sdc
or see more information about a specific device with:
lsubs -D /dev/sdc
lspci
This utility outputs a list of PCI devices attached to the system - you can produce a more verbose output with the -v switch e.g.:
lspci -v
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