Linux refers to the family of Unix-like computer operating systems using the Linux kernel. If your question is about a certain distribution only, use a more specific tag.

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What is this dm-0 device?

While poking around trying to figure out why a Linux -> Linux file transfer is running slower than I think it should, I stumbled across something I'm not familiar with. /dev/dm-0 seems to be my ...
40
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2answers
5k 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 ...
40
votes
4answers
37k views

How can I avoid SSH's host verification for known hosts?

I get the following prompt everytime I try to connect a server using SSH. I type "yes", but is there a way to aovid this? The authenticity of host '111.222.333.444 (111.222.333.444)' can't be ...
40
votes
7answers
8k views

Linux equivalent of Windows Registry

What is the Linux equivalent of Windows Registry? If there is no equivalent or similar structure in Linux, how are the things that are done by the Windows Registry handled in Linux?
40
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5answers
44k views

Read the contents of a zipped file without extraction? [duplicate]

How can I see the contents of a particular file in an archive without extracting the .zip it is contained within? I'm using the Linux command line.
39
votes
8answers
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Why is -r recursive necessary when copying a directory in Linux?

My question is why is it required to use the -r (recursive) flag when making a copy of a directory? I.e., why do this: $ cp -r dir1 copyDir1 When would I not want this behavior when copying a ...
39
votes
6answers
92k 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 ...
39
votes
3answers
35k views

How do you check how much power a USB port can deliver?

Some laptops have a special USB port that can deliver more power than the other ones. However it is not always easy to identify which one is the good one, nor how much power it can deliver. So is ...
38
votes
9answers
3k views

How to quickly change the first word in a Bash command?

I would like to improve my workflow a bit with Bash, and I realize I often want to execute the same command to a different executable. Some examples: Git (where I would like to quickly change the ...
38
votes
3answers
21k views

How to analyse disk usage in command line linux?

du and df are nice, but I don't know how to filter the data they provide the way I do with SequoiaView. I would like to know which are the largest folders and the largest files in a glance.
38
votes
5answers
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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 ...
38
votes
8answers
39k views

ffmpeg: create a video from images

Is it possible to use ffmpeg create a video from a set of sequences, where the number does not start from zero? For example, I have some images [test_100.jpg, test_101.jpg, test_102.jpg, ..., ...
38
votes
3answers
67k views

If I know the PID number of a process, how can I get its name?

If I have the PID number for a process (on a UNIX machine), how can I find out the name of its associated process? What do I have to do?
38
votes
5answers
18k 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 ...
38
votes
6answers
32k views

What is the conventional install location for applications in Linux?

I'm currently installing NetBeans, and the default install directory is /home/thomasowens/netbeans-6.8. I'm not a fan of that location, so I'm looking at /etc, /bin, /usr/bin, and /sbin. Does Linux ...
38
votes
5answers
30k 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. ...
38
votes
1answer
40k views

What is $* and $# in Linux?

What do the following environment variables in Linux mean? What is $* (dollar sign followed by an asterisk)? What is $# (dollar sign next to a hash mark/number sign/octothorpe/pound sign)?
38
votes
2answers
12k views

What's like OSX's pbcopy for Linux

In a terminal in OSX I can pipe output to pbcopy and then go into a web browser and paste it. I tried this in Linux with xcopy but when I switch to the browser it just overwrites the clipboard with ...
37
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: ...
37
votes
8answers
35k views

Best way to transfer files over a LAN between two Linux computers

I want to transfer files (a music folder) between two Linux computers. After searching for the best way to do this, I've seen that there are lots of ways of doing this. I know this has been asked a ...
37
votes
8answers
109k views

Manually closing a port from commandline

I want to close an open port which is in listening mode between my client and server application. Is there any manual command line option in Linux to close a port ?? NOTE: I came to know that "only ...
37
votes
3answers
7k views

What does the 'rc' in `.bashrc`, etc. mean?

Well, this is embarrassing. I feel like I just realised I don't know a loyal colleague's name after working with them for 10 years. "Hey, er... *cough!*, thanks for that great job you did on setting ...
37
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3answers
24k 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 ...
37
votes
2answers
53k views

Where does Google Chrome for Linux store user specific data?

Where does Google Chrome for Linux store user specific data such as bookmarks ? I can't find a .chrome or .google directory under my home directory, any other directory I should look at ?
37
votes
6answers
11k views

What happens if mv is interrupted?

What happens if the Linux mv command is interrupted? Say, I'm moving a whole directory to some other place and interrupt it while it's moving. Will the source directory still be untouched?
37
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5answers
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When should I use /dev/shm/ and when should I use /tmp?

When should I use /dev/shm/ and when should I use /tmp? Can I always rely on them both being there on Unices?
36
votes
4answers
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tmux disregarding the configuration file

I just installed tmux on Ubuntu 10.04 and tried to remap the prefix key to C-a by creating the file ~/.tmux.conf with these lines: set-option -g prefix C-a unbind-key C-b When starting tmux, both ...
36
votes
4answers
21k 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 ...
36
votes
4answers
51k views

No option to hibernate/shutdown in GNOME 3?

I have installed Fedora 15 Alpha with GNOME 3. Everything is working fine. However, I can't see any option to hibernate or shutdown. In the top panel when I click my user name, I only have one option ...
36
votes
6answers
12k views

Linux / OS X tar incompatibility – tarballs created on OS X give errors when untarred in Linux

When I tar up files on my Macbook and untar them in Linux, I repeatedly get the following warnings/errors: tar: Ignoring unknown extended header keyword `SCHILY.ino' tar: Ignoring unknown extended ...
36
votes
2answers
38k 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 ...
36
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12answers
12k views

What's a good solution for file-tagging in linux?

I've been looking for a way to tag my files and search/filter them based on those tags. Here are my (updated) requirements : any file readable by the user can be tagged freely a user can search ...
35
votes
4answers
8k views

Linux equivalent command for “open” command on Mac/Windows?

Coming from Mac OS X, you can type: $ open yourfilehere.txt and your file will open just as if you had opened it from Finder. On Windows, one can type: > start yourfilehere.txt and it will ...
35
votes
3answers
71k views

Linux: find out what process is using all the RAM?

Before actually asking, just to be clear: yes, I know about disk cache, and no, it is not my case :) Sorry, for this preamble :) I'm using CentOS 5. Every application in the system is swapping ...
35
votes
5answers
23k views

check the physical health of a USB stick in Linux

How to check the health status of a USB stick? How do I know that a USB is broken beyand repair, or repairable?
35
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5answers
14k views

How can a linux kernel be so small?

An ordinary stable 3* kernel is about 70 mb now. But there are little linux distributions of 30-10 mb with software and other stuff running out of the box. How can the linux kernel be so small in ...
35
votes
3answers
2k views

Say`vimrc`or `screenrc`, what does the `rc` mean?

What does the rc mean?
35
votes
4answers
31k views

How can I recursively copy files by file extension, preserving directory structure?

At the Linux command line, I'd like to copy a (very large) set of .txt files from one directory (and its subdirectories) to another. I need the directory structure to stay intact, and I need to ...
35
votes
2answers
78k views

Linux - Mount device with specific user rights

How can I mount a device with specific user rights on start up? I still have some problems figuring it out. I would like to mount the divide with uid=1000 and gid=1000. My current entry to the ...
35
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3answers
16k views

How do I execute multiple commands when using find?

I'm trying to run multiple commands on things I have found, how can I achieve this? find . -exec cmd1; cmd2 does not seem to work; it instead runs cmd2 after cmd1 has been executed on every file.
35
votes
4answers
2k views

Palindrome passwords disallowed—why?

I tried to change a Linux password to "sitonapotatopanotis" and got this error: BAD PASSWORD: is a palindrome Why does this rule exist?
34
votes
13answers
48k views

In Google Chrome on Linux, where is the flv if not in /tmp?

I like to keep videos because I like buffering them and then playing them back-to-back in my media player, I want to be able to stop/restart my browser without losing all the buffered video, and ...
34
votes
5answers
5k views

What is the equivalent of Linux's “~” (tilde) in Windows?

In Linux, we can go to the user home by entering the tilde (~) character after cd: cd ~ How to do the same in Windows? Each time, I need to type: cd C:\Document and Settings\freewind That's too ...
34
votes
8answers
30k views

Top causes of slow ssh logins

I'd love for one of you smart and helpful folks to post a list of common causes of delays during an ssh login. Specifically, there are 2 spots where I see a range from instantaneous to multi-second ...
34
votes
4answers
33k views

When ssh'ing, how can I set an environment variable on the server that changes from session to session?

When I ssh into a server, how can I pass an environment variable from the client to the server? This environment variable changes between different invocations of ssh so I don't want to overwrite ...
34
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2answers
5k views

How to rate-limit a pipe under linux?

Is there a filter which I could use to rate-limit a pipe on linux? If this exists, let call it rate-limit, I want to be able to type in a terminal something like cat /dev/urandom | rate-limit 3 -k | ...
34
votes
3answers
16k views

Set background image in xmonad

I have just switched from Fluxbox to giving xmonad a go, and I am definitely liking it. However, the one thing I haven't managed to do is to change my desktop background. I am using Ubuntu 8 (uh, ...
34
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1answer
36k views

Permission denied when accessing VirtualBox shared folder when member of the vboxsf group

I'm running Ubuntu 11.04 (guest) on Windows 7 (host) with the guest additions installed. I have an auto-mount folder that maps to my D: drive on the host which I can access using sudo ls ...
34
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4answers
8k views

How can I log all process launches in Linux

I would like to get a log of all processes that are launched with the time that they were launched and the arguments they were launched with. Is this possible in Linux?
33
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12answers
3k views

How do I remove a file in Linux whose name looks like it's ONLY a hyphen, as in “-”

I've tried rm -- - rm "-" rm "\-" rm \- Gave Perl a shot ~$ perl -e '$junk = glob("-"); chomp $junk; print "$junk\n"; `rm $junk`;' - rm: cannot remove `-': No such file or directory ...and... ...