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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15
votes
3answers
9k views

How can I reserve a block of memory from the Linux kernel?

I have a device that needs a block of memory that is reserved solely for it, without the OS intervening. Is there any way to tell BIOS or the OS that a block of memory is reserved, and it must not ...
15
votes
11answers
58k views

Cannot enable network after CentOS 6.3 fresh install

I am trying to perform a fresh CentOS 6.3 installation then run various yum commands such as yum install httpd. The installation runs fine, however I cannot run any network based commands like yum I ...
15
votes
2answers
1k views

Why writing to /dev/random does not make parallel reading from /dev/random faster?

Typically reading from /dev/random produces 100-500 bytes and blocks, waiting for an entropy to be collected. Why doesn't writing information to /dev/random by other processes speed up reading? ...
15
votes
5answers
9k views

Using different versions of Python

Background: Since I develop python programs that must run on different python versions, I have installed different versions of python on my computer. I am using FC 13 so it came with python 2.6 ...
15
votes
3answers
3k views

Why don't you need to update drivers? (Or do you?)

In my life I've not once updated drivers on any of my Linux systems, though they have all been desktops. A friend was asking me why one does not need to update Linux drivers and I found myself unable ...
15
votes
3answers
14k views

Extracting SFX files in Linux

I am trying to extract an SFX file under Linux Mint 15 (64 bit) but it's not working. I've done chmod +x on the file and tried to run it like a script with no luck (it gives me an error that there's ...
15
votes
5answers
13k views

How to find which process is regularly writing to disk?

How can I find which process is constantly writing to disk? I like my workstation to be close to silent and I just build a new system (P8B75-M + Core i5 3450s -- the 's' because it has a lower max ...
15
votes
3answers
9k views

How to read environment variables of a process

Linux's /proc/<pid>/environ does not update (as I understand it, the file contain the initial environment of the process). How can I read a process's current environment?
15
votes
3answers
24k views

Yum: How can I view variables like $releasever, $basearch & $YUM0?

I am setting up a yum repository, and need to debug some of the URLs in the yum.conf file. I need to know why is Scientific Linux trying to grab this URL, when I was expecting it to grab another URL: ...
15
votes
3answers
5k views

How to fix Ctrl + arrows in Vim?

I am using Putty -> Suse box -> vim 7.2 combo for editing and want to remap Ctrl + arrows combo to a particular task. But for some reason, Vim ignores the shortcut and goes into insert mode and ...
15
votes
6answers
22k views

How to see disk details like manufacturer in Linux

With sfdisk -s I can see the disk capacity as follows: $ sfdisk -s /dev/cciss/c0d0: 143338560 total: 143338560 blocks How do I see disk details like disk manufacturer? I tried hdparm, but got an ...
15
votes
5answers
2k views

Corruption-proof SD card filesystem for embedded Linux?

Recently we had a rather unpleasant situation with our customer - Raspberry Pi based "kiosk" used to display remote sensing data (nothing more fancy than a kiosk mode browser displaying a ...
15
votes
2answers
329 views

Open man page and search for string in a single command

Instead of doing man chmod and then /a+x to jump to the first section in the chmod man page that mentions a+x, I would like to know if there is a way to open the man page to a specific search string, ...
15
votes
6answers
298 views

What do I need to be aware of if I want to write an application that will run on any Linux distro?

I'm planning on writing an app that I would like to be able to run on any Linux installation without having to rewrite any of the code in doing so (except maybe the interface, GNOME vs KDE, etc). I'm ...
15
votes
5answers
3k views

How to start a new Linux distro?

Some of my friends and I are interested in starting a new Linux distro. How do we do that? What do we need to plan? Backstory I represent a community of Linux sysadmins/implementors whose special ...
15
votes
3answers
2k views

How to use three monitors on a laptop?

I have a laptop running Ubuntu 9.04 with a dual-head setup: laptop panel + external monitor. I'd like to add another monitor but the laptop has a single VGA port, so my question is: what are my ...
15
votes
5answers
24k views

Why is USB not working in Linux when it works in UEFI/BIOS?

For background I have just built a new machine with modern hardware including: AMD FX-8350 Gigabyte GA-990FXA-UD3 motherboard 16GB RAM NVidia GTX 650 Ti Kingston SSD Given that, I tried to install ...
15
votes
3answers
24k views

Can I connect to Windows machine from Linux shell?

I can connect to Linux machines from Windows using PuTTY/SSH. I want to do the other way round - connect to a Windows machine from Linux. Is this possible?
15
votes
2answers
542 views

Can I list the filesystems a running kernel can support?

I'm trying to detect what filesystems a kernel can support. Ideally in a little list of their names but I'll take anything you've got. Note that I don't mean the current filesystems in use, just ones ...
15
votes
1answer
2k views

Shebang line with `#!/usr/bin/env command --argument` fails on Linux

I've got a simple script: #!/usr/bin/env ruby --verbose # script.rb puts "hi" On my OSX box, it runs fine: osx% ./script.rb hi However, on my linux box, it throws an error linux% ./script.rb ...
15
votes
1answer
2k views

Who creates /etc/{group,gshadow,passwd,shadow}-?

In any linux system I have access to (a couple of Archlinuxes, an Ubuntu, a Debian Sid and a Gentoo) there are the following 4 files in /etc/, all ending with a dash: /etc/group- /etc/gshadow- ...
15
votes
2answers
5k views

Why does high disk I/O reduce system responsiveness/performance?

I never quite understood why high disk I/O slowed the system so much. It's strange to me because I would expect the slow-down to affect only those processes dependent on the hard/optical drive data, ...
15
votes
7answers
44k views

Unix/Linux undelete/recover deleted files

Is there a command to recover/undelete deleted files by rm? $ rm -rf /path/to/myfile How can I recover myfile? If there is such a tool how can I use it?
15
votes
1answer
19k views

How can I set up logrotate to rotate logs hourly?

According the the Unix and Linux Administration Handbook and man, logrotate has options for daily, weekly, and monthly, but is there a way to add an hourly option? This blog post mentions you can set ...
15
votes
2answers
2k views

Linux: Total swap used = swap used by processes +?

So, I'm trying to do some investigation on where does swap use come from in a system with high swap usage: # free total used free shared buffers cached Mem: ...
15
votes
3answers
330 views

How to force Linux kernel to “freeze” (or nearly freeze) for a few hundred milliseconds

We are running a real-time process on a non real-time kernel (CentOS 6), and this is probably not going to change. We have a streaming video application that requires about 500 MB/s of PCIe traffic ...
14
votes
3answers
977 views

Why do Linux people always say to read the manual? [closed]

Why do Linux people always say to read the manual when it would be so much easier to just give you an answer? There's no manual! It didn't come with one.
14
votes
2answers
2k views

Accidently created a file called -X, how can I delete it? [duplicate]

Possible Duplicate: How do I delete a file whose name begins with “-” (hyphen a.k.a. dash or minus)? Like an idiot, I ran this command: tar -cf -X awstats-icon icon ...
14
votes
6answers
79k views

How to determine Linux kernel architecture?

uname -m gives i686 and uname -m gives i686 i386 output in Red Hat Enterprise Linux Server release 5.4 (Tikanga) machine. I need to install Oracle Database 10g Release 2 on that machine. So, how can I ...
14
votes
10answers
2k views

What linux is best suited for people new to computers?

What would be the easiest linux for people who are new to computers? The computers here have 256Mb RAM with 40GB hard-disks. UPDATE: Most of them apparently have more than 265MB of RAM with some ...
14
votes
5answers
4k views

Getting information on a machine's hardware in Linux

How can I check what hardware I have? (With BIOS version etc.)
14
votes
3answers
961 views

Move files and change ownership at the sametime

On Linux (Debian, Ubuntu Mint...), Is there any option command or something that I can use to transfer files to another user without having to do : sudo mv /home/poney/folderfulloffiles ...
14
votes
6answers
46k views

Show top five CPU consuming processes with `ps`

How to show top five CPU consuming processes with ps?
14
votes
4answers
13k views

sending text input to a detached screen

I'm trying to run a minecraft server on my unRAID server. The server will run in the shell, and then sit there waiting for input. To stop it, I need to type 'stop' and press enter, and then it'll ...
14
votes
6answers
529 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) ' ...
14
votes
3answers
5k views

Understanding /dev and its subdirs and files

$ ls -l /dev/stdin /dev/fd/0 lrwx------ 1 tim tim 64 2011-08-07 09:53 /dev/fd/0 -> /dev/pts/2 lrwxrwxrwx 1 root root 15 2011-08-06 08:14 /dev/stdin -> /proc/self/fd/0 $ ls -l /dev/pts/2 ...
14
votes
2answers
5k views

Can I watch the progress of a `sync` operation?

I've copied a large file to a USB disk mounted on a Linux system with async. This returns to a command prompt relatively quickly, but when I type sync, of course, it all has to go to disk, and that ...
14
votes
3answers
4k 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
4answers
12k views

What is the equivalent of Active Directory on Linux

I have a couple of machines at home (plus a number of Linux boxes running in VMs) and I am planning to use one of them as a centralized file server. Since I am more a Linux user rather than a ...
14
votes
3answers
131k views

how to check OS and version using Linux commmand [duplicate]

what is the Linux command to check the server OS and its version? Connected the server using shell.
14
votes
4answers
474 views

How do I learn what I can do with /proc and /sys

I'd like to know more about the advanced uses of the /proc and /sys virtual filesystems, but I don't know where to begin. Can anyone suggest any good sources to learn from? Also, since I think sys has ...
14
votes
2answers
46k views

Remove GPT - Default back to MBR

I keep receiving this error: Warning!! Unsupported GPT (GUID Partition Table) detected. Use GNU Parted I want to go back to the normal MBR. I found some advice here and did: parted /dev/sda ...
14
votes
2answers
3k views

Can the same ext4 disk be mounted from two hosts, one readonly?

I know that mounting the same disk with an ext4 filesystem from two different servers (it's an iSCSI vloume) will likely corrupt data on the disk. My question is will it make any difference if one of ...
14
votes
1answer
1k views

What is Linux doing differently that allows me to remove/replace files where Windows would complain the file is currently in use?

The example I have is Minecraft. When running Bukkit on Linux I can remove or update the .jar files in the /plugins folder and simply run the 'reload' command. In Windows, I have to take the whole ...
14
votes
1answer
5k views

init process: ancestor of all processes?

I have always learned that the init process is the ancestor of all processes. Why does process 2 have a PPID of 0? $ ps -ef | head -n 3 UID PID PPID C STIME TTY TIME CMD root ...
14
votes
1answer
952 views

Why does the file command say that ELF binaries are for Linux 2.6.9?

Whenever I run file on an ELF binary I get this output: [jonescb@localhost ~]$ file a.out a.out: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked ...
14
votes
4answers
6k views

How to re-load all running applications from swap space into RAM?

If my desktop run out of memory and swaps a lot then I free or kill the application wasting my RAM. But, after that, all my desktop/applications have been swapped and are horribly slow, do you know a ...
14
votes
2answers
12k views

Reply on same interface as incoming?

I have a system with two interfaces. Both interfaces are connected to the internet. One of them is set as the default route; a side effect of this is that if a packet comes in on the non-default-route ...
14
votes
3answers
4k views

How to detect memory type under Linux?

Which Linux utility can tell me if I have registered or unbuffered ECC memory in my server? Lshw and dmidecode do not work for me; dmidecode provides no information about registered vs. unbuffered: ...
14
votes
3answers
5k views

Full disk encryption with password-less authentication in Linux

I have a fairly standard disk encryption setup in Debian 5.0.5: unencrypted /boot partition, and encrypted sdaX_crypt that contains all other partitions. Now, this is a headless server installation ...