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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14
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3answers
1k views

How to know where a program is stuck in linux?

I am running the following command on my ubuntu server root@slot13:~# lxc-stop --name pavan --logfile=test1.txt --logpriority=trace It seems to hang indefinitely. Whenever this happened on AIX, I ...
14
votes
5answers
13k views

How can I limit the bandwidth used by a process?

I have a CentOS 5.7 server that will be backing up its files nightly. I am concerned that visitors to the various sites that the server hosts will experience degraded performance while the backup is ...
14
votes
5answers
3k views

Getting information on a machine's hardware in Linux

How can I check what hardware I have? (With BIOS version etc.)
14
votes
6answers
10k views

Execute a specific command in a given directory without cd'ing to it?

Is there a way to execute a command in a different directory without having to cd to it? I know that I could simply cd in and cd out, but I'm just interested in the possibilities of forgoing the extra ...
14
votes
3answers
747 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
8answers
10k views

How to determine which sd* is usb? [duplicate]

Possible Duplicate: How to know if /dev/sdX is a connected USB or HDD? The output of ls /dev/sd* on my system is - sda sda1 sda2 sda3 sda4 sda5 sda6 sda7 sdb sdc sdc1 sdc2 ...
14
votes
3answers
2k 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 ...
14
votes
2answers
6k views

/proc/PID/fd/X link number

In Linux, in /proc/PID/fd/X, the links for file descriptors that are pipes or sockets have a number, like: l-wx------ 1 user user 64 Mar 24 00:05 1 -> pipe:[6839] l-wx------ 1 user user 64 Mar 24 ...
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
10k 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
21k 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: ...
14
votes
4answers
462 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
3answers
12k 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 ...
14
votes
3answers
8k 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?
14
votes
2answers
2k 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
4k 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
2answers
11k 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
2answers
53k views

How to find the installation path for a software under linux?

Under linux, I launch a software by typing, e.g., fluidplot. How can I find the installation path for this software?
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 ...
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
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 ...
14
votes
1answer
18k 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 ...
14
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, ...
14
votes
5answers
14k views

Check if folder is a mounted remote filesystem

What is the best way (reliable, portable, etc.) to check if a given folder is on a mounted remote (nfs) filesystem within a shell script? I am looking for a command that would look like: ...
14
votes
1answer
12k views

How to use Linux kernel driver bind/unbind interface for USB-HID devices?

First background. I am developing a driver for Logitech game-panel devices. It's a keyboard with a screen on it. The driver is working nicely but by default the device is handled by HID. In order to ...
14
votes
3answers
4k views

Are multiple @daily crontab entries processed in order, serially?

I want two jobs to run sometime every day, serially, in exactly the order I specify. Will this crontab reliably do what I want? @daily job1 @daily job2 I'm assuming they run one after the other, ...
13
votes
4answers
7k views

What is the meaning of $? in a shell script?

When going through one shell script, I saw the term "$?". What is the significance of this term?
13
votes
6answers
1k views

Can a Linux command have capital letter(s)?

Can a Linux command have capital letter(s)? I know it's supported but i want to be sure if it's a "problem" or considered "not a good thing"?
13
votes
6answers
790 views

How to achieve portability with sed -i (in-place editing)?

I'm writing shell scripts for my server, which is a shared hosting running FreeBSD. I also want to be able to test them locally, on my PC running Linux. Hence, I'm trying to write them in a portable ...
13
votes
3answers
2k views

How can I de-fragment a drive using Ubuntu?

Is it necessary to defrag drives in Ubuntu? If so, how do I do it and how often should it be done?
13
votes
6answers
6k views

What's the best way to partition your drive?

I usually install Linux on a single partition since I only use it as a personal desktop. However every now and then I reinstall the box and what I simply do is to move my files around with an ...
13
votes
3answers
760 views

Do different distros (but same kernel ver) have same hardware support

As far as I know the device drivers are located in the Linux kernel. For example let's say a GNU/Linux distro A has the same kernel version as a GNU/Linux distro B. Does that mean that they have the ...
13
votes
3answers
16k views

Which users are allowed to log in via SSH by default?

When I set up my Debian 6, I was wondering, which users apart from root whose password I know can log into my system via SSH? When I install Apache 2 a user called www-data gets created. Does this ...
13
votes
4answers
936 views

Is there any reason why I get ^[[A when I press up arrow at the console login screen?

Whenever I'm at the console login, I press up arrow intentionally to see the previously typed commands. But I see this ^[[A. But when I press Ctrl Alt Print Screen Scroll Lock Pause Break Page Up ...
13
votes
3answers
3k views

Automatically rename files when they are placed in a specific directory

Is it possible to automatically rename a file when it's placed in a specific directory? For example I have a directory named "dir0".I move or copy a file named "file1" to "dir0".then "file1" should ...
13
votes
2answers
1k views

How secure is keeping non-root owned scripts in /etc/init.d?

I have an application which runs as a daemon and is controlled by a script in /etc/init.d Sometimes we need to change some parameters of startup/control of these scripts and then restart the daemon. ...
13
votes
5answers
11k 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 ...
13
votes
2answers
4k 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 ...
13
votes
2answers
6k views

What is the proper sudoers syntax to add a user?

According to the comments in /etc/sudoers (Fedora 13): ## Syntax: ## ## user MACHINE=COMMANDS ## ## The COMMANDS section may have other options added to it. My two related questions: What ...
13
votes
3answers
621 views

Contents of /proc

Is there a site someplace that lists the contents of /proc and what each entry means?
13
votes
3answers
4k 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 ...
13
votes
2answers
26k views

What is the difference between ioctl(), unlocked_ioctl() and compat_ioctl()?

Going through the linux 2.6.36 source code at lxr.linux.no, I could not find the ioctl() method in file_operations. Instead I found two new calls: unlocked_ioctl() and compat_ioctl(). What is the ...
13
votes
1answer
229 views

Bash No Longer Changes Directory

My bash shell will no longer change directory with cd. I noticed it earlier when working and found that any new shells I opened (terminal or xterm etc) would be stuck in the home directory and could ...
13
votes
2answers
38k 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 ...
13
votes
3answers
1k views

How can I keep control+d from disconnecting my session?

I regularly ssh to a centos 5 box. Somehow they keys are mapped so that control+d will log me out of my current shell. If I am sudo'ed to another use it puts me back to the previous user. If I am not ...
13
votes
4answers
5k 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 ...
13
votes
1answer
435 views

What happens when you rsync without a destination?

To make the story short, I did an rsync: rsync -avP root@exampleserver.com:/tmp/ And I forgot to put in my source directory... :( I really meant to run: rsync -avP /tmp/ ...
13
votes
1answer
20k views

How to use command line to change volume?

I am trying to control the volume using my programming script. How can I do the following in Fedora 15, Ubuntu linux? Mute/ Unmute Volume up and volume down Note: Please note that I use a web USB ...
13
votes
4answers
769 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 ...