Questions specifically about Linux, as opposed to Unix-like systems in general, or to questions about a specific distribution or program.

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6 views

Is that safe to use kfifo (not a _spinlock flavour) in fiq/nmi handlers? [migrated]

Basically need to pass variable-size records to and from FIQ handler (ARM platform). During any get/put operation on kfifo (on the user-space/kernel side only) I am going to disable all IRQs and ...
-1
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0answers
16 views

You don't have permission to access /dokuwiki on this server

There is a dokuwiki installed in a server that works fine before. One day the IP of this server is changed. When I access dokuwiki with new IP, the browser states "You don't have permission to access ...
1
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0answers
16 views

What does ipq_ctl do?

I'm in the process of writing some rust bindings to libipq, and I came across an undocumented function in libipq.h: int ipq_ctl(const struct ipq_handle *h, int request, ...);. However, this doesn't ...
1
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0answers
46 views

How do I configure SSHd to require 2 (or more) passwords to log in

I'm asking because I want to setup a server that cannot be administered by any single admin, not without the permission (and oversight) of one other authorized admin (there can be many). Since there ...
1
vote
1answer
25 views

linux nat different rules

eth0 (192.168.1.0/24) --> wan eth2 (192.168.10.0/24) --> lan0 I use these rules to enable NAT on my linux gateway: iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE iptables -A FORWARD -i ...
1
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0answers
45 views

How do I view multiple users groups using sssd?

SETUP OS = RHEL 6.4 Workstation System is part of an LDAP domain and was originally configured to authenticate using nscd. All recommended SSSD packages have been installed. ...
4
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2answers
35 views

Can I mount a case-insensitive tmpfs/ramfs?

I would like to utilize the performance of tmpfs/ramfs for some file operations, but the programs/processes that use these files assume a case-insensitive file system. I cannot find any documentation ...
1
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1answer
28 views

How to find bandwidth usage/bytes transmitted/received within a certain time frame

I'm looking for a way to get numbers on bandwidth usage of an eth port. But I need to filter the results to only show me numbers for the last 24 hours. Or any time period in hours or minutes. Just ...
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0answers
17 views

how to use postfix alias for sending email

I am not this question has been asked or not, I have postfix running with MySQL and recently i have created "support@example.com" alias email to multiple folks get email, just like distribution list. ...
2
votes
2answers
101 views

how to grep for specific time period in a log

We work with log files that have line entries that start with a date/time format such as this: 20150408 13:29:28 <rest of text> What would I need to do in order to grep for a date range? Say ...
0
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0answers
11 views

What's wrong with my Arch linux grub bootup? [closed]

So ever since I did a fresh install of Arch Linux, every time it boots up and I select the Grub option it says "A start job is running for /dev/drive/" and shortly after it says timed out and ...
1
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1answer
29 views

How can I set permissions on a windows share from linux client

I want to write a script to set permissions on a windows share from linux client. I know that I can use smbclient, cifs or smbfs to mount windows share from linux. But I have no idea how to set ...
1
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0answers
29 views

Route wireless LAN through OpenVPN

I am trying to set up my home server to act as an OpenVPN gateway so I can connect to my VPN from any device without installing special software of them. My server is running Ubuntu 14.04. The host ...
0
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1answer
42 views

Set home directory of a user to root?

I would like to set the home directory for ftpuser to root. That's my command: # adduser ftproot -shell /bin/false -home /var/www What is the directory term for root?
2
votes
0answers
278 views

Can I make the boot even more verbose than loglevel=7 using kernel parameters?

I have an error when booting on a machine, my machine is stuck with the error message: Booting a command list. I can see this message when I add loglevel=7to the kernel parameters via grub boot ...
0
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2answers
17 views

non-breaking space sometimes appears in Geany (my standard text editor)

I use Geany for all my coding, in my linux Mint-MATE install. Occasionally, i have a problem where a non-breaking space (char code 194) is present instead of a normal space character (32). This just ...
1
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0answers
14 views

How to route vpn traffic over hostapd-raspberry pi

I have a raspberry pi running hostapd and I am able to connect my laptop as a wifi client to the raspberry bi wifi router. The problem is with the vpn traffic, I cant connect to my office vpn with ...
1
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0answers
29 views

Loud persistent fan on Linux Mint 17 with discrete graphics card

I've been running Linux Mint 17 for the last half year with no fan problems, but last week the laptop fan turned on and hasn't stopped since. I hadn't messed around with bumblebee or nvidia drivers ...
0
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0answers
13 views

Increase multipathed filesystem journaling threads?

We have some hardware which is utilizing multipath to speak to backend storage. A situation has been observed which some are attributing to too few journaling threads being allocated by the kernel. ...
2
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1answer
15 views

Mount iscsi drive at boot - system halts

I am running Oracle Linux 7 (CentOS/RH) in a Virtual Box VM on a Mac with OS X 10.10. I have a Synology Diskstation serving as an iscsi target. I have successfully connected to the Synology, ...
3
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0answers
24 views

How to generate graphs from lmbench results?

I need to use the lmbench benchmarking tool to get the system performance statistics. I am able to execute and run the results. In the results folder this is a MakeFile with this information # ...
1
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1answer
36 views

Saving power on a linux cluster

I would like to buy a cluster (30-60 nodes) for work and install linux on it. The cluster should have a queue system like PBS, for instance. It should also be capable of doing parallel computation. I ...
0
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1answer
126 views

broadcom BCM43142 under kali linux

I am trying to get the wireless card of my laptop (Broadcom BCM43142) to work under kali linux (latest version, 64bit). At the moment (without installing anything), it is not recognised at all. I have ...
1
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0answers
10 views

Using apprarmor/grsec to gain capabilities for file

I know that using apparmor, one can reduce process capabilities(7). But is it possible to gain them? For example: ping requires CAP_NET_RAW. It's binary has no suid set and doesn't have any file ...
3
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2answers
17 views

How and where is file system meta data cached in Linux

My earlier question apparently had a wrong premise. I thought file system meta data was cached in the inode and dentry cache, but apparently not. When I do: # time find . > /dev/null real ...
1
vote
1answer
38 views

Remapping Caps Lock to Compose

Because I now and then need to use scandinavian letters despite using US Dvorak as my layout, I would like to use Caps Lock as a compose key. (I don't need Caps Lock at all, I'm not a forum troll) ...
3
votes
1answer
52 views

Remount a busy disk to read-only mode

I want to force a disk partition to read only mode and keep it read-only for more than 30 minutes. What I have tried: mount -o remount,ro (partition-identifier) (mount-point) -t (filesystem) ...
0
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0answers
25 views

How should my program behave to handle errors? [migrated]

I have written a program (with code from SO) that does printenv | sort | less and now I should implement error-handling. How can that be done? The program should fail gracefully, for example when ...
1
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0answers
33 views

Svn Error on import time no space left on device

When I import file in svn repository I get following error . svn: E000028: Failed writing updated file: No space left on device Following is mine diskspace and inode details # df -i ...
1
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2answers
39 views

Systemd dependency tree saving

As I know systemd stores dependencies between services in unit files. I need to know how systemd behaves on boot: Does it load unit files from specific paths and recalculate dependencies every time ...
0
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0answers
34 views

Connect multiple bluetooth devices to multiple bluetooth usb adapters

I have lots of bluetooth devices that need to connect to a Raspberry Pi. Currently I have a scanner script that locates and connects to each device. My current limitation is the fact that a one ...
0
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0answers
23 views

I chowned / recursively. How can I restore default permissions? [duplicate]

In a completely boneheaded moment, I ran the following command: #chown -R user:usergroup . What I failed to realize is that I was in the root directory, not in my target directory. Now the entire ...
0
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0answers
22 views

Incorrect installation of python-2.7.2 - cannot use zlib

I am installing python 2.7.2 from Python-2.7.2.tar on Linux Ubuntu-14.04. I untar it, then ./configure --prefix=/apps/python/install/2.7.2. I then make and get : Python build finished, but the ...
0
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0answers
21 views

Centos 6-7 install argument for GUID Partition Table

From here http://www.tecmint.com/centos-7-installation/ item 11 NOTE:For those users, who have hard-disks more than 2TB in size, the installer automatically will convert partition table to GPT, ...
1
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2answers
33 views

how can i chmod the files based on the results from find command

I have a situation where I need to find the files having World Write (WW) permission 666 and I need to re mediate such files with 664 .. for this I have used this command find /dir/stuct/path -perm ...
0
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2answers
54 views

How to run multiple AND in grep command [duplicate]

I'm trying to run multiple AND combination in grep command, I was able to run using two patterns: grep -E 'pattern1.*pattern2' filename Is it possible to use three or four patterns using the above ...
0
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0answers
30 views

how to find out why process is taking more cpu usage

Sometimes load goes high on server for java processes. Multiple java processes are running and consuming high load on server. I want to know how to check that why process is taking too much load.
0
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2answers
68 views

Linux or Unix online practice environment [closed]

I want to learn Linux or Unix, but I don't want to install on my machine. Is there any site or any other way to practice Linux online?
2
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1answer
19 views

Why do I get different results with the same user and the history command?

I work with Linux for quite some time and have seen this behaviour but I never got a good explanation. Probably it's even very simple. If I login twice with the same user (bash) in the same server ...
0
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2answers
54 views

Awk one-liner to print column of SQL table?

Suppose I have table like: This is first line name minimum maximum config_value ----------------------------------- ----------- ----------- ------------ some ...
0
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0answers
35 views

How to fix: /usr/lib64/libstdc++.so.6: version `GLIBCXX_3.4.15' not found

I need to install doctotext hence in the base directory, I run doctotext.sh and I got the following error (./doctotext: /usr/lib64/libstdc++.so.6: version 'GLIBCXX_3.4.15' not found). When I did ...
-1
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1answer
18 views

separate the system & hardware clock in linux

I want to separate the system clock from the hardware clock which I synchronize first. But now I want to change both: hardware clock with the UTC time & system with the GPS time.
0
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1answer
36 views

Create and report system acivity

I have a set-up a server running several applications. There will be multiple people using these applications in a community situation. I am looking for a way to track and report changes made to ...
1
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0answers
9 views

how to know present carry flag in assembly code? [migrated]

I've been reading and studying assembly code. Code is below Disassembly of section .text: 08048510 <main>: 8048510: 8d 4c 24 04 lea 0x4(%esp),%ecx 8048514: 83 e4 ...
0
votes
0answers
28 views

How to forward range ports in my linux server?

Is there any tools to do range port forwarding in my CentOS system? Just like any ports from 8000 to 9000 shoud be forwarded another IP's 8000~9000 respectively. I know it's easy to be done in Router ...
2
votes
4answers
260 views

Is it viable to run Live Linux on a Laptop with a failing hard drive?

I have determined using Hiren's Boot CD that my hard drive is in fact failing. It started by failing to boot into Windows or Linux partitions on my computer, and then I downloaded Hiren's, burned to a ...
0
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0answers
23 views

how __libc_start_main@plt works? [migrated]

To study how the object file loaded and run in linux, I made the simplest c code, file name simple.c. int main(){} Next, I make object file and save object file as text file. $gcc ./simple.c ...
2
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0answers
19 views

Is there a thing like “veth”, but without link-level headers?

When I use separate network namespace, I often set up networking there using veth: ip link add type veth ip link set veth0 netns 1 ifconfig veth1 192.168.60.2 ip route add default via 192.168.60.1 ...
1
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1answer
45 views

cfdisk or fdisk?

While reading the man page for fdisk I came across this interesting text: There are several *fdisk programs around. Each has its problems and strengths. Try them in the order ...
2
votes
2answers
57 views

What's the closest you can get to rebooting without killing all running processes?

How can I get the effect of rebooting on refreshing the system (freeing resources and reinitialising them) without killing most of the things I have running? Could I unload and reload kernel modules? ...