procfs (or the proc filesystem) is a special filesystem in UNIX-like operating systems that presents information about processes and other system information in a hierarchical file-like structure

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File delete versus overwrite and link at /proc/pid/fd

It is well known that UNIX systems won't actually delete a file on disk while the file is in use. So if a file is being accessed by process 1 and process 2 deletes the file using rm, process 1 ...
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Utility which gives line from /proc/id/maps by specific address

Is there an utility that gives me specific line from /proc/id/maps when given specific address from this process? For example when given 0x7fb4a84f6008 it returns: 7fb4a84f6000-7fb4a84fd000 r-xp ...
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Dirty in /proc/meminfo for dd

I read from here that the below command gives me the amount of data that needs to be written to the disk. grep ^Dirty /proc/meminfo It particularly says Ever ask yourself "How much data would be ...
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Is there a way to identify which process turns into Zombie process

One of the ubuntu server has 82 zombie processes. All processes shows '[sh] defunct' as process command. Is there a way to find out which process is becoming a zombie process? I tried checking the ...
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parsing process ID/names from /proc, thread IDs

When I'm parsing process IDs from /proc, obviously each thread of a process gets its own ID. And I realize that all the threads in that same process can be gathered from /proc/${pid}/task/. But my ...
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How run free command by crontab

I want to run this command: free && sync && echo 3 > /proc/sys/vm/drop_caches && free -m by cron that why I'm able to free my RAM and cache in ubuntu system. I'm using ...
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Is there a faster interface for info from /proc/net/tcp?

Given a linux TCP socket's inode (obtained via /proc/<pid>/fd), is there a faster way to look up the information that I can get from /proc/net/tcp about this socket? I have written a ...
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The amount of time since the system was last booted [duplicate]

I have used both uptime and cat /proc/uptime commands. I know the idle time in the later can be greater than running time (multiprocessors). However, when I add both running and idle times, and ...
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Busybox ash script does not exit cleanly after executing cat; unable to get exit code

Consider the following script wrapcat.sh (a wrapper for cat) for illustrative purposes. It is run with busybox (ash) in an embedded Linux 2.6 box. #!/bin/sh cat $1 Under certain circumstances, this ...
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files in /proc/$PID (e.g. ssh-agent, Chrome) are not owned by user but by root

I am just answering another question here :-) and thus had a look – wanted to have a look at /proc/$PID/fd of ssh-agent in order to find out which socket it uses. But I can't. I am quite surprised to ...
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What is the connection between jiffies and IPS? How to convert jiffies to IPS?

Reading from /proc/PID/stat a lot of information can be processed. I would like to see how many percentages has been used of CPU power by this process. There are a lot of variable around here (utime, ...
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Disk i/o latency using /proc/vmstat file

How do i calculate Disk read and write latency in Linux? Is it possible to do the calculation using /proc file system? I am used iostat and vmstat command. But i do not understand how the ...
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Significance of Linux kernel's default_console_loglevel

What is the significance of default_console_loglevel in Linux? Commonly I see it described as the default value of console_loglevel. However, what that means I haven't seen explained anywhere. ...
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170 views

Monitor the creation of new processes

I want to get a notification whenever a new process is created. I've tried to use inotify on /proc, but it didn't report any event even though a new directory appeared in /proc. I could list the ...
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What are the /proc/drivers directories organisation for nouveau or radeon

The context: I need to get some basic informations from the graphic card in a lib in lua. The idea is to not rely on external software (like hwinfo for example). I know that for a system with an ...
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193 views

Programmatically get CPUs 'detailed' usage, like top/htop

htop has a great way to show CPU usage. It shows the activity (usage in %) of each cores, and each core gauge is divided into three parts : blue: low priority processes green: normal processes red: ...
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/proc/self/maps - 3rd mapped piece of file?

I'm running Arch linux on my laptop, which is kernel 3.12.9 right now. Something has changed about the way the kernel maps in a dynamically-linked executable and I can't figure it out. Here's the ...
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/proc/cpuinfo showing zero cpu clock speed

I saw an interesting issue where the cpuinfo file from /proc filesystem shows the cpu clock speed as zero. It is a physical host with no virtualization. Can someone explain to me some probable reasons ...
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/proc/net/wireless does not show values unless run as root

cat /proc/net/wireless does not show statistics for wireless devices unless it is run as root, even though the permissions on the file are 444. The same seems to apply when accessing statistics via ...
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“ps” output and comments

I'm pretty sure you cant do this but maybe someone has some weird hack... Is there a way to get comments (#blahblah) to show up in ps output? My problem is that i have a script, lets call it ...
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How can I disable /proc pseudo-filesystem on a shared Linux environment?

Is it possible to disable the /proc pseudo-filesystem to prevent w, ps, top, etc, from showing what other users are doing? Of course, I still want "everything else" to work correctly. Is there a ...
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Making Bootable USB, problems copying /proc

I'm creating a bootable usb as a cloned partition and am running into problems copying /proc to the usb. I know /proc contains a lot of virtual files, but I'm not sure how to copy them over. It seems ...
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Wrong eUID in `/proc/PID/status` when SETUID is used

While doing a wargame challenge, I ran into an issue with permissions. The info given by /proc/PID/status is not in adequation with the permissions that should be given to the processus. I am user ...
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Read “/proc” to know if a process has opened a port

I need to know if a process with a given PID as opened a port without using external commands. I must then use the /proc filesystem. I can read the /proc/$PID/net/tcp file for example and get ...
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Memory usage of a given process (using Linux proc filesystem)

I want to know which files from /proc directory and which fields of these files I need to calculate the memory usage of a given pid. I've been using the "stat" file and the "vsize" parameter that is ...
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Directory in /proc that isn't process dir but start with number?

Quick question. Is it possible to create directory in /proc that starts with number but isn't process directory (where name is PID)? I write software that searches for process directories and I wonder ...
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List running processes without procfs

I'd like to list running process (like using ps or top), but there is no procfs mounted. The procfs not being mounted is intentional, and is made to prevent malicious user to access systems ...
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653 views

With “find /”, skip directories like “/proc”, “/sys” and similar [duplicate]

There are some directories that can cause problem with find, and especially find /. These are directories in which the OS creates files which are not really files. Among these directories are /proc ...
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how to determine the max user process value?

Which value is correct?(or they are all correct, but which one will take effect?) $ cat /proc/sys/kernel/pid_max 32768 $ ulimit -a |grep processes max user processes (-u) 77301 $ cat ...
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Modify 'Soft Limit' of 'Max processes'

I tried ulimit -u 2000 and ulimit -Su 2000 to modify the 'Max processes', and started up my program, but failed. I found file '/proc/pid/limit' is still: Max processes 1024 ...
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Ubuntu: /proc/pid/comm file missing

On my development box, under /proc/[pid]/ there is a file called comm containing the name of the executable for that process. I use this to validate the process to which I am sending a signal. On our ...
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812 views

How to clone a read-only portion of /proc file system

The problem with reading /proc file system is that it is not atomic. I tried using a library (procfs in Python) that wishes to read it, but it has glitches about 5% of the time because the process ...
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209 views

Looking for /procfs documentation, describing values and units of measurement

Surprisingly, comprehensive documentation for /procfs is hard to find. For my specific question, I am looking at: cat /proc/1/statm (let's use pid=1 because it seems to be always there). I just ran ...
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583 views

vmstat on virtual machine and large values

Hi I'm using vmstat to track machine performance during some tests (jmeter). This is virtual machine running on a big machine where lots of other virtual machines are installed (about 20 virtual ...
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Is there any way to read files from the virtual /proc directory using smbclient?

Is there any way to read files from the virtual /proc directory using smbclient? No root access. Both server and client are Debian Linux machines. Server is running Samba 3. Smbclient version is ...
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219 views

lsof: measure I/O rate of a socket fd

I'm writing a script that parses the output of lsof to show a list of what processes have sockets open (similar to what netstat shows). lsof also gives me a file descriptor. What I want to do now is ...
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186 views

processor(s) statistics that is one day old

I already know how to use grep -w cpu /proc/stat in order to get the cpu stats and identify the user mode. Percentage wise, I just divide it my the total time from the /proc/uptime. However, how can ...
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419 views

Do kernel counters for jiffies in state exist in Linux?

I am looking to get time/jiffie stats on the state of a daemon process. The states I'm referring to are mentioned in the Linux Kernel Proc Filesystem document. Running, Sleeping, uninterruptible ...
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390 views

About sector and blocks, and a little confusion in /proc/diskstats

I've been studying about diskstats lately, and I get that the amount of hdd read comes in sectors. But in most places I've noticed that there exists a slight misunderstanding about sectors and blocks. ...
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What does the “ss -s” result “Total:” value represent? How to get details on each of them?

I am trying to understand what the ss -s result line Total: value represents, along with how this number is related to the other numbers. Note, the following values are equivalent: ss -s Total: == ...
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What do the fields in /proc/net/ipt_hashlimit/FILE mean?

What do the fields in /proc/net/ipt_hashlimit/FILE mean? These files are created upon iptables -A CHAIN -m hashlimit--hashlimit-name FILE [...] [...] 9 198.51.100.23:0->0.0.0.0:0 80000 80000 160 ...
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Inconsistent output on /proc. Can some processes be hidden? [duplicate]

When I list /proc/<PID>, works as expected. But when I use ps or ls /proc | grep <PID>, the process is hidden. How & Why is this possible? [user@host ~]$ ls /proc/12263 attr ...
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What is kswapd_low_wmark_hit_quickly from /proc/vmstat

What does this parameter mean? # cat /proc/vmstat | grep low kswapd_low_wmark_hit_quickly 2
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How to know file name of sockets or pipes in /proc/[pid]/fd

In Android, #ls -l 15843/fd gives following output, lrwx------ u0_a179 u0_a179 2015-05-28 11:58 90 -> socket:[193728] lrwx------ u0_a179 u0_a179 2015-05-28 11:58 91 -> ...
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What are possible reasons why iwconfig is not updating connection stats?

I use iwconfig to show me some information about my current internet connection like this $ iwconfig wlp2s0 IEEE 802.11abg ESSID:"eduroam" Mode:Managed Frequency:2.462 GHz Access ...
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How can I get read/write instant speed of a Hard Drive using /proc/diskstats data?

I know that the proc/diskstats file presents these data columns: 1 - major number 2 - minor mumber 3 - device name 4 - reads completed successfully 5 - reads merged 6 - sectors read 7 - time spent ...
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Constant 60KB Shared library memory on /proc/<pid>/maps

In a quest for understanding RAM requirements of system processes, I arrived to analysis of /proc/pid/maps. I have noticed a pattern: many shared libraries have exactly 60KB space allocated in their ...
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How to see kernel time variables without using adjtimex?

The man page for adjtimex says Anyone may print out the time variables, but only the superuser may change them. How do I see the value shown by adjtimex -p as the tick variable without using ...
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/proc/stat - is guest counted into user time?

I have a quick question. In man page for /proc/stat this is not clear to me: Is guest and guest_nice time included in user time in /proc/stat? http://man7.org/linux/man-pages/man5/proc.5.html in ...
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How is /proc/net files getting populated in Linux/Unix?

I'm working on a network monitor for Linux, without packet sniffing. I'm planning to read the network statistics and related data from /proc/net files. I know that /proc is the mount point of process ...