You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
174 lines
6.0 KiB
174 lines
6.0 KiB
= An Introduction to Linux !
|
|
Apostolos rootApostolos@swarmlab.io
|
|
// Metadata:
|
|
:description: Intro and Install
|
|
:keywords: Linux, apt
|
|
:data-uri:
|
|
:toc: right
|
|
:toc-title: Table of contents
|
|
:toclevels: 4
|
|
:source-highlighter: highlight
|
|
:no-header-footer:
|
|
:nofooter:
|
|
:last-update-label!:
|
|
:icons: font
|
|
:sectnums:
|
|
|
|
|
|
{empty} +
|
|
|
|
|
|
|
|
.procfs
|
|
****
|
|
The proc filesystem (*procfs*) is a special filesystem in Unix-like operating systems that presents information about processes and other system information in a hierarchical file-like structure,
|
|
*providing* a more convenient and *standardized method for dynamically accessing process* data held in the kernel than traditional tracing methods or direct access to kernel memory.
|
|
|
|
Typically
|
|
|
|
- it is mapped to a mount point named /proc at boot time.
|
|
|
|
- The proc file system acts as an interface to internal data structures in the kernel.
|
|
|
|
- It can be used to obtain information about the system and to change certain kernel parameters at runtime (sysctl).
|
|
|
|
****
|
|
|
|
|
|
== The /proc Filesystem
|
|
|
|
NOTE: The proc filesystem provides a method of communication between *kernel space* and *user space*. For example, the GNU version of the process reporting utility *ps* uses the proc file system to obtain its data, without using any specialized system calls.
|
|
|
|
|
|
The directory /proc contains (among other things) one subdirectory for each process running on the system, which is named after the process ID (PID).
|
|
|
|
The link ‘self’ points to the process reading the file system. Each process subdirectory has the entries listed in: ls /proc/<pid>
|
|
|
|
|
|
|
|
[source,bash]
|
|
----
|
|
cat /proc/meminfo
|
|
|
|
|
|
MemTotal: 8174328 kB
|
|
MemFree: 6186516 kB
|
|
MemAvailable: 7535332 kB
|
|
Buffers: 146740 kB
|
|
Cached: 1294156 kB
|
|
SwapCached: 0 kB
|
|
Active: 967184 kB
|
|
Inactive: 606252 kB
|
|
Active(anon): 135620 kB
|
|
Inactive(anon): 85064 kB
|
|
Active(file): 831564 kB
|
|
Inactive(file): 521188 kB
|
|
Unevictable: 3652 kB
|
|
Mlocked: 3652 kB
|
|
SwapTotal: 0 kB
|
|
SwapFree: 0 kB
|
|
Dirty: 68 kB
|
|
Writeback: 0 kB
|
|
AnonPages: 136188 kB
|
|
Mapped: 113344 kB
|
|
Shmem: 85724 kB
|
|
Slab: 340236 kB
|
|
SReclaimable: 302048 kB
|
|
SUnreclaim: 38188 kB
|
|
KernelStack: 3792 kB
|
|
PageTables: 4888 kB
|
|
NFS_Unstable: 0 kB
|
|
Bounce: 0 kB
|
|
WritebackTmp: 0 kB
|
|
CommitLimit: 4087164 kB
|
|
Committed_AS: 901432 kB
|
|
VmallocTotal: 34359738367 kB
|
|
VmallocUsed: 0 kB
|
|
VmallocChunk: 0 kB
|
|
HardwareCorrupted: 0 kB
|
|
AnonHugePages: 51200 kB
|
|
CmaTotal: 0 kB
|
|
CmaFree: 0 kB
|
|
|
|
...
|
|
----
|
|
|
|
|
|
|
|
|
|
|
|
|
|
.Main entries in /proc
|
|
[options="header,footer"]
|
|
|=======================
|
|
|File|Content
|
|
| /proc/cmdline | – Kernel command line information.
|
|
| /proc/console | – Information about current consoles including tty.
|
|
| /proc/crypto | - a list of available cryptographic modules
|
|
| /proc/devices | – Device drivers currently configured for the running kernel.
|
|
| /proc/diskstats | - giving some information (including device numbers) for each of the logical disk devices
|
|
| /proc/dma | – Info about current DMA channels.
|
|
| /proc/fb | – Framebuffer devices.
|
|
| /proc/filesystems | – Current filesystems supported by the kernel.
|
|
| /proc/interrupts, /proc/iomem, /proc/ioports and the directory /proc/irq | - giving some self-explanatory details about the devices (physical or logical) using the various system resources
|
|
| /proc/iomem | – Current system memory map for devices.
|
|
| /proc/ioports | – Registered port regions for input output communication with device.
|
|
| /proc/loadavg | – System load average.
|
|
| /proc/locks | – Files currently locked by kernel.
|
|
| /proc/meminfo | – Info about system memory (see above example).
|
|
| /proc/misc | – Miscellaneous drivers registered for miscellaneous major device.
|
|
| /proc/modules | - one of the most important files in /proc, containing a list of the kernel modules currently loaded . It gives some indication (not always entirely correct) of dependencies.
|
|
| /proc/mounts | – List of all mounts in use by system.
|
|
| /proc/mounts | - a symlink to self/mounts which contains a list of the currently mounted devices and their mount points (and which file system is in use and what mount options are in use).
|
|
| /proc/net | - a directory containing useful information about the network stack, in particular /proc/net/nf_conntrack, which lists existing network connections (particularly useful for tracking routing when iptables FORWARD is used to redirect network connections)
|
|
| /proc/partitions | – Detailed info about partitions available to the system.
|
|
| /proc/pci | – Information about every PCI device.
|
|
| /proc/stat | – Record or various statistics kept from last reboot.
|
|
| /proc/swap | – Information about swap space.
|
|
| /proc/scsi | - giving information about any devices connected via a SCSI or RAID controller
|
|
| /proc/sysvipc | - containing memory-sharing and inter-process communication (IPC) information.
|
|
| /proc/tty | - containing information about the current terminals; /proc/tty/driver looks to be[original research?] a list of the different types of tty available - each of which is a list of those of each type
|
|
| /proc/uptime | – Uptime information (in seconds).
|
|
| /proc/version | – Kernel version, gcc version, and Linux distribution installed.
|
|
|=======================
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
== cpu info
|
|
|
|
|
|
[source,bash]
|
|
----
|
|
cat /proc/cpuinfo
|
|
|
|
processor : 0
|
|
vendor_id : AuthenticAMD
|
|
cpu family : 16
|
|
model : 6
|
|
model name : AMD Athlon(tm) II X2 270 Processor
|
|
stepping : 3
|
|
microcode : 0x10000c8
|
|
cpu MHz : 2000.000
|
|
cache size : 1024 KB
|
|
...
|
|
processor : 1
|
|
vendor_id : AuthenticAMD
|
|
cpu family : 16
|
|
model : 6
|
|
model name : AMD Athlon(tm) II X2 270 Processor
|
|
stepping : 3
|
|
microcode : 0x10000c8
|
|
cpu MHz : 800.000
|
|
cache size : 1024 KB
|
|
----
|
|
|
|
|
|
|
|
|