Questions specifically about Linux but not specific to a particular distribution. If the question could apply to any Unix-like system, specify your Linux distribution in the body of your question but do not use the /linux tag.

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15
votes
3answers
6k views

(How) can I create a tmpfs as a regular (non-root) user?

The distribution is an Ubuntu server running the 2.6.35-30 Linux kernel. I would like to have a directory that sits completely in memory. Is this possible without root privileges?
14
votes
6answers
1k views

Showing only “interesting” mount points / filtering non interesting types

I used mount to show mounted drives, I don't want to see the not so interesting ones (i.e. non-physical). So I used to have a script mnt that did: mount | grep -Ev 'type (proc|sysfs|tmpfs|devpts) ' ...
8
votes
3answers
637 views

Open Source router firmware options?

What distro's exist that are designed for routers? Please include the following link to the project page link to supported hardware list what distinguishes them, why pick this option friendly web ...
5
votes
1answer
3k views

Does kernel: EDAC MC0: UE page 0x0 point to bad memory, a driver, or something else?

kernel: EDAC MC0: UE page 0x0, offset 0x0, grain 0, row 7, labels ":": i3200 UE All of a sudden today, our CentOS release 6.4 (Final) system started throwing EDAC errors. I rebooted, and the errors ...
5
votes
1answer
1k views

Tracking huge buffer usage under Linux

I have a Linux server running under Debian Lenny with 4Go of RAM. It doesn't run much, just: Postfix/spamassassin (daemon mode) Bind9 KVM (one guest - 1Go of RAM for it) Every day at exactly 3:05 ...
5
votes
1answer
2k views

I don't want other users see my processes in ps aux. I have root. It's Debian. How to use grsec?

I installed 'linux-patch-grsecurity2' and it has some sort of interface. ~$ sudo gradm2 gradm 2.1.14 grsecurity administration program Usage: gradm [option] ... Examples: gradm -P ...
4
votes
1answer
160 views

Shared library mappings in /proc/pid/maps

Why does /proc/pid/maps contain a few records for the same library ? Here is an example: 7fae7db9f000-7fae7dc8f000 r-xp 00000000 08:05 536861 ...
4
votes
3answers
1k views

Are there any ways or tools to dump the memory cache and buffer?

As the title, I want to check out what files are loaded in buffer. Just so it's clear, the buffers & cache I'm referring to are what show up when you run the free -m command: $ free -m ...
3
votes
1answer
2k views

per process private file system mount points

I was checking unshare command and according to it's man page, unshare - run program with some namespaces unshared from parent I also see there is a type of namespace listed as, mount ...
3
votes
2answers
1k views

How to change environment variables without re-logging to UI?

How can I change environment variables without re-logging to UI? I want to re/define some variables and want them set on my current logged in shell (including UI). I know logging out and then logging ...
3
votes
1answer
2k views

LVM2 partition alignment

How to do the following with Linux tools : LVM partition alignment and alignment of partition on LVM ? What in case where I want to setup LVM partition (for "pv") and then partitions ? To be more ...
23
votes
1answer
15k views

Linux: What is a tainted kernel?

Under certain conditions, the Linux kernel may become tainted. For example, loading a proprietary video driver into the kernel taints the kernel. This condition may be visible in system logs, kernel ...
16
votes
4answers
9k views

Binary compatibility between Mac OS X and Linux

Brace yourselves, this question will likely appear naive and/or foolish, seeing as I am relatively new to the inner workings of unix like systems, and programming in general. Ready? Ok! I will go ...
13
votes
1answer
6k views

What does a dot after the file permission bits mean?

I performed an ls -la on directory on my CentOS 6.4 server here and the permissions for a given file came out as: -rwxr-xr-x. I understand what -rwxr-xr-x means, what I don't understand is the . ...
8
votes
2answers
682 views

Cleaner way to delete files on Linux which include a datestamp as part of file name

I have a new requirement to purge MySQL dump files that are older than 30 days. The files use a naming convention of "all-mysql-YYYYMMDD-HHMM.dump". The files are located on SAN mounted file system, ...
8
votes
3answers
10k views

64-bit Linux doesn't recognize my RAM between 3 and 32 GB

My problems were caused by a faulty memory module and quite possibly a broken kernel binary. I just now booted my PC with basically brand new hardware. I've been running Debian 6.0 AMD64 before, ...
8
votes
2answers
4k views

Why does top report the incorrect CPU usage?

I have a machine with Intel(R) Xeon(R) CPU E5520 visible as 16 logical cores (8 with HT). If I run something to eat CPU time (single threaded) top correctly reports 100% CPU usage for the process but ...
7
votes
1answer
5k views

Read what is written to /dev/tty*

How can I read what is written to /dev/tty*(* = 0 - number of tty)? I tried sudo tail -f /dev/tty1 on one terminal(X) and then sudo cp .emacs /dev/tty1 from another. X didn't show the the content of ...
7
votes
4answers
3k views

What are the advantages of the Unix file system structure

If I install an application in Linux for example Debian/Gnu Linux, the files of the applications are copied to many different directories in the file system. Some scripts goes into /usr/share .. ...
5
votes
1answer
271 views

How does gnome reboot without root privileges?

I am reading the book Linux kernel development, in chapter 5 "System Call Implementation" page 77 says For example, capable(CAP_SYS_NICE) checks whether the caller has the ability to modify ...
5
votes
3answers
3k views

Remove all lines in file A which contain the strings in file B

I have a CSV file users.csv with a list of userNames, userIDs, and other data: username, userid, sidebar_side, sidebar_colour "John Lennon", 90123412, "left", "blue" "Paul McCartny", 30923833, ...
4
votes
2answers
1k views

How to parallelize dd?

I'm currently having trouble with dd invoked with a sparse file as input (if) and a file as output (of) with conv=sparse. dd seems to be using one core of the CPU (Intel(R) Core(TM) i7-3632QM CPU @ ...
4
votes
1answer
3k views

Automatically detect when a file has reached a size limit

I would like to send an email when a file reach a certain size limit. The only way I thought of doing this is by doing a cronjob which will check the file size and send the email if the file is ...
4
votes
2answers
3k views

256 color in Linux console

I have in my .bashrc export TERM=xterm-256color but this cause blinking all colored text (ls --color, in vim etc.) in a Linux console (Ctrl+Alt+F1). So is there any possibility to recognize in ...
4
votes
2answers
2k views

Remapping caps-lock to escape, and menu to compose, on the linux console

When running X I use a .xmodmaprc to remap certain keys thusly: ! Make it so that both Caps Lock and Escape do Escape clear Lock keysym Caps_Lock = Escape ! Remap the menu key as Compose keysym Menu ...
3
votes
1answer
399 views

Obtaining information about system hardware

If I want to accurately save information about the hardware I am using as a reference, what is the best way to do it? Are the contents of /proc/meminfo sufficient?
2
votes
1answer
1k views

Fedora's command-not-found doesn't work

I've recently installed Fedora 19. Packagekit-command-not-found is installed. But its own examples don't work. When I enter gedti the output is: bash: gedti: command not found... Similar command is: ...
7
votes
4answers
8k views

Understanding of diff output

I have file1.txt this is the original text line2 line3 line4 happy hacking ! and file2.txt this is the original text line2 line4 happy hacking ! GNU is not UNIX if I do: ...
7
votes
2answers
794 views

How to disable system beep for non-privileged user

How to disable system beep on Linux? I don't have superuser powers so I cannot recompile kernel/unload module.
6
votes
2answers
3k views

Edid information

I want to gather the Edid information of the monitor. I can get it from the xorg.0.log file when I run X with the -logverbose option. But the problem is that If I switch the monitor (unplug the ...
5
votes
3answers
11k views

RHEL: Creating stable names for network interfaces

We have a RHEL 5.5 box with 8 interfaces. And the eth interface naming is flip flopping. Sometimes eth0 comes up on physical port 7th, and sometimes on another physical port. We want the naming to ...
5
votes
3answers
803 views

Why does sed act differently depending on the output file?

If I run: cat messages.txt | sed -e 's/a/a/g' > messages.txt on one large file (2500+ lines) I find that the resulting file will only have about 900 lines after the command in cygwin and will ...
4
votes
5answers
981 views

Multiple terminals at once without an X server

There is a way to visualize multiple terminals at the same time without running a Xorg session ? I have a really low profile machine that could be great for some basic stuff but has an horrible ...
4
votes
2answers
6k views

Disable direct login for normal users (like oracle) in linux but allow scp and sftp?

Is it possible to disable direct login for normal users (like oracle) in linux but allow scp and sftp for that use?
3
votes
1answer
918 views

Route SSH to host through interface

Is it possible to route all outgoing requests for SSH (port 22) to mydynamicdns.afraid.org via wlan0 instead of eth0 when both are connected? Since my IP is dynamic, I would like to use a name ...
3
votes
1answer
2k views

tty (console): disable monitor

In .xinitrc, I use xrandr --output LVDS1 --off to disable the monitor of my laptop (I always use a projector at school). But, before I log in with xinit, or when I temporary go to the console ...
2
votes
2answers
369 views

Creating a Debian package that does not remove directories after it's purged

I'm trying to create a Debian package that doesn't delete an empty directory after it's purged. Specifically, I'm creating my own package containing some CA certificates I trust. I'm following ...
2
votes
3answers
473 views

What is the difference between ./script and . ./script? [duplicate]

Possible Duplicate: Using ‘.’ to execute files in bash I was trying to figure out how to export my environmental via script instead of changing my .bashrc file. I found this old useful ...
2
votes
1answer
434 views

Debian unstable chroot security issues

This page describes how you can use the debootstrap utility to install a base Debian unstable/sid system on an existing Linux machine. The new install is accessible using chroot. When doing this, ...
1
vote
2answers
49 views

Fsck script location

I need to find out what kind of script runs fsck during the boot on CentOS 7? I know that all scenarios are located in /etc/rc.d directory. But I haven't any idea about where is this script is ...
1
vote
1answer
200 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) ...
1
vote
1answer
329 views

Always Forward Traffic Out The Interface It Originated On

(This is the original question but my eventual solution was too different from how I originally asked the question so I'm posting as a new question.) Background: I have a VM with three different ...
1
vote
0answers
150 views

How to determine which init system is used? [duplicate]

Is there a way to determine which init system is being used in Linux? (such as sysvinit, upstart, systemd, etc.) I don't care if it can be programmatically determined, I just want to know how I can ...
1
vote
2answers
3k views

Running Linux kernel in Virtualbox

I just built a Linux kernel on Ubuntu and now I want to make it run on VirtualBox. I wanted it to be in an img format. I created a hard drive image by doing the commands: $ qemu-img create disk.img ...
0
votes
2answers
141 views

Run script and not lose access to prompt / terminal

I am running jmeter by launching the .sh script, once I do that I cannot start using the prompt again unless I ctrl-z, ctrl-c, or the script ends in some other way. How can I launch that script and ...
0
votes
1answer
2k views

Debian and Systemd: breaking ordering cycle error

I'm a new embedded developer I'm trying to make systemd 37 work with freescale vybrid board (A5 and M4) running on linux-3.0 After boot with some breaking ordering cycle error, I check with ps ...
86
votes
12answers
268k views

How do I set my DNS when resolv.conf is being overwritten?

Most of the info I see online says to edit /etc/resolv.conf, but any changes I make there just get overridden. $ cat /etc/resolv.conf # Dynamic resolv.conf(5) file for glibc resolver(3) generated by ...
70
votes
7answers
107k views

What to do when a linux desktop freezes?

I'm a Windows guy, dual booted recently, and now I'm using Linux Mint 12 When a Windows desktop freezes I refresh, or if I am using a program I use alt + F4 to exit the program or I can use ctrl + ...
61
votes
5answers
43k views

What are high memory and low memory on Linux?

I'm interested in the difference between Highmem and Lowmem: Why is there such a differentiation? What do we gain by doing so? What features does each have?
100
votes
3answers
111k views

Why do I need a tty to run sudo if I can sudo without a password?

I have configured sudo to run without a password, but when I try to ssh 'sudo Foo", I still get sudo: sorry, you must have a tty to run sudo. Why does this happen and how can I work around it?