Proc file system

Proc File Sys

Proc file system:- virtual file system contains real time system information

/proc

Contains diff files and directories depending on your system hardware.

Few files and directories information

/proc/buddyinfo :- contains information about memory fragmentation dma shows first 16 mb of memory and highmem containing info about ram above 4gb while normal contains information about ram b/w dma and highmem.

/proc/cmdline :- contains information about parameters passed to kernel at boot time

e.g ro root=/dev/VolGroup00/LogVol00 rhgb quiet 3

root is mounted as readonly on first logical vol on first volgroup

rhgb means graphics graphics mode booting is on and quiet tell that kernal messages on boot time are surpressed and 3 is the default runlevel which is set in inittab file id:3:initdefault:

/proc/cpuinfo :- displays full information about the processors

processor : 0 means only one is present

/proc/crypto :- display cryptographic ciphers used for kernal

eg. sha1 , md5

/proc/devices :- display the devices whose modules are loaded will not display modules which are present but their modules are not installed

it shows characters and block devices.

Differences b/w characters and block devices:-

character devices don't have buffers while block devices have e.g hard drives

/proc/fb :- frame buffer contains frame buffer device name

/proc/filesystems :- displays all the filesystems suppored by kernel.

*** mount command cycles through this list when mounting a device when no file system is specified.

/proc/iomem :- shows current memory mapped for diff i/o devices

/proc/ioports :- lists currently registered i/o ports for a device

/proc/kmsg :- contains messeages generated by the kernel which are picked by /sbin/klogd or /bin/dmesg

/proc/loadavg :- displays the load average of system and i/o system load , total processes currently running and last column displays the pid of last process started.

/proc/locks :- displays the lock status of various files

/proc/mdstat :- displays status of raid on system

/proc/meminfo :- displays full sys memory information

/proc/misc :- displays miscellaneous devices status

/proc/modules :- displays all the information related to modules loaded to view formated output use lsmod

/proc/mounts :- lists all mounts in system

/proc/mtrr :- memory type range regiseres

/proc/partitions :- partitions details of the system

/proc/stat :- displays staus of system after the reboot

/proc/uptime :- first column displays system uptime in sec and second column system idle time

/proc/version :- displays current sys kernel, gcc version and os details

Proc dir contains a lot of directories with numerical names, which are actully process id's which holds full information about that process.

Group and owner of the dir

file details of process id directorie :-

cmdline :- contains command issued to start the process

cwd :- contains symbolic link to current working dir for the process

envirn:- contains environment variables for the process

exe :- symbolic link to executable of the process

df :- contains all the file descriptors for a particular process

maps :- memory maps of the process

mem :- memory held by the process.

Stat and status:- status of the process

statsm :- memory usuage statistics of the process.

Root :- link to the root directory of the process.

/proc/self/ :- list to self process

There are a lot more things which depend on your system configuration