Ubuntu is a Linux distribution with an emphasis on ease of use and installation. Note that http://askubuntu.com is specifically dedicated to Ubuntu questions.

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61
votes
19answers
8k views

Root access that can't change root password?

We are having a little problem on a server. We want that some users should be able to do e.g. sudo and become root, but with the restriction that the user can't change root password. That is, a ...
53
votes
7answers
15k views

What is the Linux equivalent to C:\Program Files?

I understand that in Windows as well as Linux and Unix, a program|application|software can be installed in any directory. Also if packages are installed using the distribution's packaging system, ...
36
votes
1answer
9k views

What is $debian_chroot in .bashrc?

What is the debian_chroot variable in my bashrc file? and what is it doing here? PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
29
votes
8answers
23k views

How to copy text from vim to an external program?

I'm trying to copy-paste some text from vim. I'm doing v to enter visual mode, then y once I selected my block. It appears to copy the text into vim's clipboard, because p will paste it. But in ...
28
votes
2answers
21k views

How do I run 32-bit programs on a 64-bit Debian/Ubuntu?

I have a 64-bit (amd64 a.k.a. x86_64) Debian or Ubuntu installation. I need to run 32-bit (i386/i686) programs occasionally, or to compile programs for a 32-bit system. How can I do this with a ...
26
votes
8answers
47k views

How do I set my DNS on Ubuntu 14.04?

Most of the info I see online says to edit /etc/resolv.conf, but any changes I make just get overridden. $ cat /etc/resolv.conf # Dynamic resolv.conf(5) file for glibc resolver(3) generated by ...
25
votes
6answers
20k views

Differences between Debian and Ubuntu

I'm getting sick of Ubuntu's seemingly random changes. I'm thinking of switching to Debian permanently. Does anyone know if there's a list of changes between the two distros somewhere? I want to know ...
22
votes
9answers
8k views

List explicitly installed packages

In Gentoo there is the file /var/lib/portage/world that contains packages that I explicitly installed. By explicit I mean, packages that I choose, not including anything installed by default, or ...
22
votes
7answers
6k views

Force directory to always be in cache

I've been testing out different methods to improve the time it takes to compile my entire c++ project. Currently it takes ~5 minutes. I experimented with distcc, ccache, and others. Recently, I ...
22
votes
1answer
5k views

What does adduser do that useradd doesn't?

In addition to the more widespread useradd, Debian based systems also contain an additional adduser command which provides a higher level interface for adding users and some related tasks. There are ...
22
votes
1answer
6k views

Run script on screen lock/unlock

I'd like to run a screen if the Gnome session is locked and unlocked. Is there a way that I can intercept this and perform certain actions when the desktop is locked or unlocked?
20
votes
4answers
6k views

What doesn't need defragmentation? Linux or the ext2 ext3 FS?

Why don't you have to defrag a Linux system? Because it's using the ext2/ext3 file system or because it's Linux? That's relevant, because a have a double boot system (W7 / Ubuntu) and a common ...
20
votes
4answers
15k views

How can I play a sound when script execution is ready?

I am executing every now and then some python scripts which take quite long to execute. I execute them like this: $ time python MyScript.py How can I play a sound as soon as the execution of the ...
19
votes
4answers
19k views

How to record Skype video calls on Linux?

I'd like to conduct recorded video interviews with Skype and am looking for a reliable tool to accomplish that. Is there anything out there that's not slow or buggy? I'm running (K)Ubuntu.
18
votes
4answers
2k views

What makes CentOS “enterprisey” compared to “generic” distributions like Ubuntu?

What makes CentOS "enterprisey" compared to "generic" distributions like Ubuntu? When I say "enterprisey" I actually mean "better for server deployments". Just a general question, because I was ...
18
votes
4answers
33k views

File permission issues with shared folders under Virtual Box (Ubuntu Guest, Windows Host)

I am using Ubuntu on Virtual Box and I have a folder which is shared between the host (Windows) and the VM (Ubuntu). When I open any file in the share folder in Ubuntu, I can not change it as its ...
17
votes
3answers
6k views

bulk rename (or correctly display) files with special characters

I have a bunch of directories and subdirectories that contain files with special characters, like this file: robbie@phil:~$ ls test�sktest.txt test?sktest.txt Find reveals an escape sequence: ...
17
votes
1answer
3k views

Meaning of colours in htop

Given the option: [ ] Detailed CPU time (System/IO-Wait/Hard-IRQ/Soft-IRQ/Steal/Guest) In htop (Version 1.0.1) what are the meanings of the colours? In the following image, I'm seeing rather a lot ...
16
votes
6answers
27k views

Ubuntu12.04: How to disable a daemon process at startup

I normally use service start/stop or initctl start/stop to start or stop a daemon process but now what I am looking for is to disable a daemon process from starting at startup example mysqld. ...
16
votes
2answers
835 views

Is there an online/web interface to search and list apt-get packages and see summaries and recommendations?

I'm looking for sort of an 'app-store' or Google Play store type functionality for apt-get packages. What I'd really like to do is select a category, like 'Music' or 'Internet' and see the list of ...
16
votes
3answers
1k views

How to prevent shutdown when an SSH user is logged in?

I'm administrating a networked environment and I had an interesting situation arise yesterday. When a host is required to shutdown by a regular user, it refuses to do so if other users are logged in ...
15
votes
5answers
3k views

Advantages of Debian over Ubuntu

What are the main advantages of using Debian instead of Ubuntu?
14
votes
5answers
7k views

What is the difference between ls and l?

I accidentally typed l instead of ls today and found that the command still printed a list of the files in my current directory. Trying l --help brings up the help file for ls suggesting that l is ...
14
votes
4answers
450 views

What specific vulnerabilities am I creating by disabling the sudo password?

Here are some instructions on how to disable your sudo password. These carry the following warning If you disable the sudo password for your account, you will seriously compromise the security of ...
14
votes
5answers
10k views

rsync all files of remote machine over SSH without root user?

I have this command to backup a remote machine. The problem is that I need root rights to read and copy all files. I have no root user enabled for security reasons and use sudo the Ubuntu way. Would I ...
14
votes
3answers
57k views

“Input/output error” when accessing a directory

I want to list and remove the content of a directory on a removable hard drive. But I have experienced "Input/output error": $ rm pic -R rm: cannot remove `pic/60.jpg': Input/output error rm: cannot ...
14
votes
3answers
26k views

Shell script fails: Syntax error: “(” unexpected

I've been working on a script that automates setting up a development environment for Raspberry Pi development (step by step details that work are here). The script is linked in that article but ...
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
6answers
2k views

Is there a root password on OS X and Ubuntu?

When you setup a new Ubuntu or OS X installation a user is generally created for you. On OS X it is whatever username you pick. On Ubuntu (the server version) usually the ubuntu user is created. The ...
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
2answers
3k views

(SSH) Is it dangerous to close terminal without “exit”?

This happened many times. While the SSH active, I'm so tired and just close the terminal without exit Is it dangerous to doing like that?
13
votes
2answers
9k views

What is the proper way to manage multiple python versions?

I have a machine with Python 2.6 installed as the default Python. Then, I installed Python 2.7, and manually created /usr/bin/python as a symlink to the new installation. Then, I was running into ...
12
votes
3answers
12k views

Linux, disable /dev/fd0 (floppy)

Is it possible to make Linux kernel completely ignore the floppy disk controller? I do not have the drive but obviously my motherboard does contain the controller. I would like to disable the /dev/fd0 ...
12
votes
3answers
3k views

Why don't my arrow keys work in sh?

I recently installed Ubuntu and when I run sh on the Terminal my arrow keys don't work so I can't go through my call history or edit whatever I'm typing. It just comes out as weird characters like ...
12
votes
4answers
1k views

In Debian based systems, how do we purge configuration files of packages that have already been uninstalled?

To be more specific, I would like to do the equivalent of adding the --purge flag to the following command sudo apt-get autoremove --purge [package name] to packages that are no longer on the ...
12
votes
1answer
7k views

How do I set a user's default .bashrc file?

On Ubuntu 10.4 I have edited the /etc/bash.bashrc file to set some variables like the command history size (HISTSIZE=5000), however if I create a new users Ubuntu by default gives them a .bashrc file ...
12
votes
1answer
3k views

What happens in each step of the Linux kernel-building process?

I've read many tutorials about how to build custom kernels and boot Ubuntu using those kernels, and successfully followed the guides and booted custom kernels, but I have no understanding about what ...
12
votes
1answer
1k views

How do I make my laptop sleep when it reaches some low battery threshold?

I'm using Ubuntu, but I have i3 as my window manager. Under i3, when my battery reaches 0%, the computer will just abruptly shut down, no warning or anything. Is there a simple script or ...
11
votes
4answers
37k views

SSH login with clear text password as a parameter?

I need to login to a user that I've created on a remote host running Ubuntu. I can't use an ssh key because the ssh login will happen from a bash script ran within a server that I wont have access to ...
11
votes
4answers
18k views

What program do I use to check mail?

I'm receiving "You have mail" messages and according to How to remove “You have mail” welcome message I should read my mail with mail. However I cannot find the command in my system (Ubuntu 10.04 ...
11
votes
7answers
10k views

Linux equivalent for Windows Startup

Is there any way to add an application/script to the Linux startup so every time the system is on it executes [i'm looking for some automated way, user should not add this by cron job or something ...
11
votes
5answers
535 views

Is there a more succinct alternative to piping to wc for counting files in a directory

If I do ls -1 target_dir | wc -l, I get a count of files in a directory. I find this a bit cumbersome. Is there a more elegant or succinct way?
11
votes
7answers
809 views

Can I label a disk device rather than a partition?

I know about the e2label and friends program for attaching a label to a disk partition e.g. e2label /dev/sda1 bla What I want to do is something different: I want to create a label for a hard ...
11
votes
2answers
3k views

Why is vi apparently broken (viminfo error E576), and how can I fix it?

I am proficient at using Unix/Linux, but I am not an expert. If I want to open a file (for example, file.txt), I use vi: vi file.txt This opens the file, and if I want to close it, I use :q!. I ...
11
votes
4answers
11k views

XFS vs Ext4 vs Others - which file system is stable, reliable, for long run such as 24/7 case [closed]

XFS and Ext4 file system which one is really stable and reliable for long run with heavy disk write and read? the system will be used in a place where 24/7 is in service, and every second there is ...
11
votes
5answers
6k views

Screen turns on automatically (xset dpms force off)

I am using xset dpms force off to manually turn my screen off to save power. However, it turns back on after some time (20 - 40 seconds). Distro: Ubuntu-Lucid Graphics: Intel 4500 MHD ...
11
votes
1answer
4k views

What does a kernel source tree contain? Is this related to Linux kernel headers?

In books, I typically read references to the Linux Source Tree at /usr/src/linux with the usual set of subdirectories (arch, block, crypto, ...). I was expecting this tree to contain the binary files ...
11
votes
5answers
16k views

How do I set up dual monitor wallpaper (Ubuntu/NVIDIA)?

On Ubuntu 10.4 with NVIDIA drivers I have dual monitors setup with TwinView. How do I configure a single wallpaper to span both monitors? Right now the same wallpaper is replicated on both monitors. ...
11
votes
1answer
2k views

How can I monitor CPU usage by user?

I need to monitor CPU usage by users of two servers' (Ubuntu and CentOS). For example: user1 5% user2 10% ... Is there a tool similar to top or htop that can do that?
11
votes
2answers
1k views

Is it possible to simulate installation of Debian packages, still marking them installed?

Here's what I would like. Start with a virtual system with no installed packages. Then I invoke a tool similar to apt-get to ask it to compute the dependencies and mark all the packages that would be ...