The procfs filesystem is mounted under the /proc directory and contains live data about what is running on the computer. Even everything is stored as text, do not open the files with an editor. The editor might crash since it gets never ending data. Use cat instead. e.g. cat /proc/cpuinfo shows you how much bogomips your computer has.


The device specific information is successively moved away from the proc directory into the /sys directory. As example the /proc/bus/usb is now found under /sys/bus/usb and the devices file is for backward compatibility reasons added under /sys/kernel/debug/usb/devices. For details see the kernel documentation usb/proc_usb_info.txt

Many system programs do nothing else than reading the data out of/proc.

man proc and read the details. Some Examples:

cat /proc/partitions

Shows the drives attached

cat /proc/cmdline

Shows how the kernel got booted

The number directories in/proc are equal to the PID's (process ID's).

cat /proc/1/status

Shows the status about PID 1 (known as init the first program started)

cat /proc/loadavg

returns 5 values:

  1. 3 average system load values over the last 1,5 and 15 minutes

  2. number of running processes plus sum of all processes

  3. last active PID

cat /proc/uptime

returns 2 values:

  1. time in seconds since system start

  2. idle time in seconds since system start

cat /proc/meminfo

returns everything about the memory

cat /proc/kmsg

returns last kernel messages

cat /proc/version

returns version of Linux and gcc used

cat /proc/cpuinfo

returns everything about your cpu

cat /proc/devices

returns the running devices

cat /proc/interrupts

returns configured interrupts. The number shows how many interrupts already occurred. Additionally device driver handling the interrupt can be seen.

cat /proc/filesystems

The supported file systems nodev indicated that this file system does not require a device.

cat /proc/dma

The supported DMA channels

cat /proc/ioports

The io ports of your computer

cat /proc/cmdline

The command line used to start the kernel.

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