Free, open-source operating system based on Debian GNU/Linux. Ubuntu questions are on topic here, but if you prefer an Ubuntu-only audience there is AskUbuntu.com.

learn more… | top users | synonyms

199
votes
10answers
228k views

How to check which apache modules are enabled/installed?

Which is the most elegant way to check which apache modules are enabled?
180
votes
14answers
167k views

How do I detach a process from Terminal, entirely?

I use Tilda (drop-down terminal) on Ubuntu as my "command central" - pretty much the way others might use GNOME Do, Quicksilver or Launchy. However, I'm struggling with how to completely detach a ...
165
votes
8answers
82k views

Find what package a file belongs to in Ubuntu/Debian?

I frequently find myself missing a program, man page, or other file when working on my Ubuntu 8.04 system. Is there any simple way to look up what package contains a given file (whether it is ...
132
votes
7answers
53k views

How to tell from what Ubuntu or Debian repository a package comes?

On a Debian-based system, including Ubuntu, how can one tell which repository a package will be downloaded from, without actually beginning the download? aptitude show and apt-cache info will show the ...
121
votes
5answers
308k views

How to mount a HFS partition in Ubuntu as Read/Write?

I plugged in my external harddrive (which was formatted on my Mac into HFS+ journaled) to my Ubuntu desktop 9.04 64bit. I am not able to get the drive to mount with write capability, how do I do ...
120
votes
8answers
53k views

Running upstart jobs as unprivileged users

What's the canonical way to have an upstart job change its userid and run the script as an unprivileged user? Obviously one can use su or sudo, but this seems hacky (and can generate needless log ...
112
votes
5answers
255k views

How can I list all IPs in the connected network, through Terminal preferably?

Using Ubuntu 10.10, I was wondering if there was a command line command that can list all the IPs of devices connected to the network? I would use this for example, to list all the computers ...
105
votes
6answers
206k views

How can I monitor the CPU temperature under linux?

How do I monitor and display the CPU temperature using Linux?
102
votes
16answers
167k views

How to wipe free disk space in Linux?

When a file is deleted, its contents may still be left in the filesystem, unless explicitly overwritten with something else. The wipe command can securely erase files, but does not seem to allow ...
97
votes
3answers
186k views

How do I install the Sun/Oracle Java SDK on Ubuntu?

Since 11.10 Ubuntu does not provide the sun-java-jdk, how do I install it?
89
votes
5answers
44k views

Aptitude vs. apt-get: Which is the recommended (aka the “right”) tool to use?

Some time ago I read that aptitude is the preferred tool for installation on Debian-based systems. But when you search around on how to administer a Debian-based system, then aptitude is rarely ...
83
votes
1answer
82k views

How to reload /etc/environment without rebooting?

/etc/environment is officially the correct place for system wide environment variables. But how can I reload the assignments in this file without rebooting or relogging? Interestingly enough google ...
82
votes
9answers
65k views

Run VirtualBox in background, without a window?

I was wondering if it's possible to run an Ubuntu virtual machine using VirtualBox in background, I mean, without any window open. The idea is to connect via SSH to the Linux host, that would be ...
78
votes
3answers
49k views

How can I launch the GNOME image viewer from the terminal?

It's the default image viewer for Ubuntu, and apparently it's called Eye of Gnome. I would like to be able to launch it from the command line, passing it a file name to open.
75
votes
16answers
92k views

How to synchronize the home folder between multiple computers?

I have three computers at home, and would like to have the /home/ folder tree synchronized between the three. Any files/folders (except those hidden) that are modified/added/removed in one of the ...
73
votes
5answers
147k views

How do I create an administrator user on Ubuntu?

I want to create a user having sudo powers in Ubuntu. How can I do that?
71
votes
5answers
94k views

How to password protect gzip files on the command line?

I want to create some tar.gz (and possibly tar.bz2) files, using the tar command on Ubuntu 10.04. I want to password protect the file. What is the command to do this (I have Googled, but found ...
60
votes
5answers
124k views

How do you add a certificate authority (CA) to Ubuntu?

My work has decided to issue their own certificate authority (CA) to handle different aspects of our work securely without paying for certificates. Cryptographically sign emails Encrypt email ...
59
votes
5answers
26k views

Zsh not hitting ~/.profile

I've just installed zsh on my Ubuntu system. It seems zsh isn't executing ~/.profile on init. To my best understanding, this should be an automatic behavior. What am I missing?
59
votes
6answers
4k views

Is there a point in installing antivirus on Ubuntu?

I have recently started using Ubuntu. I am wondering about the point of installing antivirus programs on Ubuntu. On SuperUser, I found the opinion that it only detects "windows viruses" and removes ...
59
votes
4answers
12k views

What are “Super Cow Powers” and why doesn't my aptitude have them?

sudo aptitude help aptitude 0.4.11.11 Usage: aptitude [-S fname] [-u|-i] aptitude [options] <action> ... Actions (if none is specified, aptitude will enter interactive mode): ... This ...
58
votes
9answers
86k views

How do I add a user to multiple groups in Ubuntu?

What's the command line utility and the arguments it requires?
58
votes
11answers
78k views

Automatically mount external drives to /media/LABEL on boot without a user logged in?

This question is similar, but kind of the opposite of what I want. I want external USB drives to be mounted automatically at boot, without anyone logged in, to locations like /media/<label>. I ...
57
votes
5answers
70k views

what does the asterisk mean after a filename if you do ls -l

I've done an ls -l inside a directory, and my files are displaying like this : james@nevada:~/development/tools/android-sdk-linux_86/tools$ ll total 9512 drwxr-xr-x 3 james james 4096 2010-05-07 ...
56
votes
9answers
50k views

Change default text editor for crontab to vim

I'm using ubuntu 9.10 and the default text editor is nano, which i hate. (doesn't everyone?) Normally it's not a problem as i just vi or gedit everything but crontab -e is opening with nano. I ...
56
votes
6answers
36k views

Is there a way to show notification from bash script in Ubuntu?

Most of the application can show nicely formatted notification on events that appear on top right corner of the screen. I'm about to write a bash script that will do fairy long processing in the ...
54
votes
6answers
4k views

What is a simple way to let a command run for 5 minutes? [duplicate]

Is there an easy way to let a specific command (only terminable through Ctrl-C) run for 5 minutes automatically? For example: minute-command 5-minutes ping www.google.com or any other command that ...
54
votes
4answers
70k views

How do I make Bash my default shell on Ubuntu?

I have a .bash_profile in my home directory, but it isn't getting run on login. If I do the following, then things seem to be as I expect: ssh myhost bash source ~/.bash_profile But normally that ...
54
votes
8answers
174k views

How to upload one file by FTP from command line?

I need to upload a single file to FTP server from Ubuntu. This operation should be done in a script (in non-interactive mode). What is the right syntax for ftp? I'm trying this, to no avail: $ ftp ...
53
votes
5answers
40k views

VirtualBox to use dual monitors

I am am running Kubuntu Hardy Heron, with a dual monitor setup, and have VirtualBox on it running Windows XP in seamless mode. My problem is, I can't get virtualbox to extend to the second monitor. ...
50
votes
5answers
11k views

Why is my dual-core CPU recognized as a quad-core one?

My processor is an Intel Core i3-380m. As you can see, it's 2 cores and 4 threads. Although, both Ubuntu 11.04 and Windows 7 seem to think it's a quad-core CPU: Why is this? Is it because there ...
49
votes
4answers
31k views

Mac OS X “say” command in Ubuntu?

Is there an equivalent to the Mac's terminal command "say" in Ubuntu 9.10?
48
votes
2answers
34k views

How to add a mp3 handler to sox?

I want to play music in the terminal with sox. # install sox/lame sudo apt-get install sox sudo apt-get install lame # play music play music.mp3 # play FAIL formats: no handler for file extension ...
48
votes
4answers
118k views

How do I log out of `sudo su`?

I'm using sudo su to start mysql and do some homework with it. When I finish with mysql (or any other command), then I'm still in sudo. How do I "log out", so my prompt changes back from # to $?
48
votes
4answers
118k views

How to update Google chrome in Ubuntu?

How to update Google chrome in Ubuntu?
47
votes
11answers
20k views

What is the relationship between Unix, Linux, Ubuntu, Debian and Android?

What is the relationship between Unix, Linux, Ubuntu, and Debian? I suspect they are all Operating Systems that are based upon one another - similar to how Windows is based on DOS. Is my suspicion ...
46
votes
6answers
120k views

How do I restart Linux (Ubuntu) from the command-line?

Because of my problem with mouse-clicks being ignored in Ubuntu, I want to restart from the command-line. (I have an open Terminal, and the keyboard is not ignored.) How do I restart a computer ...
46
votes
6answers
29k views

Better Ubuntu Fonts

I have been using Ubuntu for a while. I like it. I like it a lot. But once in a while, when I switch to Windows, I feel better because I really like the font. It feels really much pleasant to watch ...
45
votes
5answers
65k views

How to determine available free space on Ubuntu?

I am in a situation where I am getting an error when I try to save a file to my Ubuntu server via ssh. It says there isn't any available space left. I don't know how that can be true. What should I do ...
45
votes
6answers
26k views

Getting macro keys from a Razer BlackWidow to work on Linux

I picked up a Razer BlackWidow Ultimate that has additional keys meant for macros that are set using a tool that's installed on Windows. I'm assuming that these aren't some fancypants joojoo keys and ...
44
votes
3answers
20k views

Convert a PDF to greyscale on the command line in FLOSS?

I have a colour PDF file, and I'm going to print it out and then photocopy it in black and white. I'd like to know what it's like in B&W before photocopying it. Is it possible to 'greyscale' a PDF ...
42
votes
3answers
75k views

How can I change shell in Ubuntu? [duplicate]

I have a Ubuntu Server VPS and I want to use /bin/bash/ as my shell. How can I change my shell? I have root access but I don't work as root. So dash is my default shell now. I have read How do I make ...
42
votes
2answers
7k views

what is the difference between “command && command” and “command ; command”

I see these two usage on Ubuntu "command && command" and "command ; command", e.g. apt-get update && apt-get upgrade What would differ if I use apt-get update; apt-get upgrade? I ...
42
votes
3answers
61k views

How to install an updated version of PEAR / PHPUnit on Ubuntu?

Most tutorials online show how to install PEAR by doing this: sudo apt-get install php-pear This installs version 1.6.1. It works great because it's super easy! My problem is that I want to install ...
42
votes
4answers
28k views

How to make cut/copy/paste in GVim on Ubuntu work with Ctrl+X,Ctrl+C,Ctrl+V?

By default, the cut/copy/paste short-cuts in GVim on Ubuntu are: Cut "+x Copy "+y Paste "+gP I would like to use control key combos in GVim, like I use in Firefox and othe gnome ...
42
votes
2answers
6k views

Why would the Wi-Fi connection on my smartphone perform better than the same connection on my laptop?

The download speeds while connected on Wi-Fi to the same router—an ADSL2+ Wireless N300 Modem Router—seems to be significantly faster on my phone than on my laptop. This problem doesn’t occur all the ...
41
votes
6answers
69k views

tar: Exiting with failure status due to previous errors

I have written a little script that tars and compresses a list of directories + files. The script appears to run succesfully, in that a useable .tar.gz file is created after the script runs. ...
41
votes
3answers
30k views

Ubuntu shutdown fail “* Killing all remaining processes…”

I have a fresh installation of Ubuntu Server. "reboot" works, but shutdown fails on the * Killing all remaining processes... step. I am using: sudo shutdown now After the failure, indicated by ...
40
votes
2answers
56k views

Can I create an SSH user which can access only certain directory?

I have a Virtual Private Server which I can connect to using SSH with my root account, being able to execute any linux command and access all the disk area, obviously. I would like to create another ...
38
votes
7answers
3k views

How can a Linux OS be “based on” another Linux OS?

I've been looking through quite a number of Linux distros recently to get an idea of what's around, and one phrase that keeps coming up is that "[this OS] is based on [another OS]". For example: ...