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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How to get list of dependencies of non-installed RPM package?

apt-cache show <package> shows also it's dependencies. yum info <package> does not show dependencies, but it obviously know them. How to ask yum for dependencies of specified package?
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10answers
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How to extract text with OCR from a PDF on Linux?

How do I extract text from a PDF that wasn't built with an index? It's all text, but I can't search or select anything. I'm running Kubuntu, and Okular doesn't have this feature.
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4answers
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How to update Google chrome in Ubuntu?

How to update Google chrome in Ubuntu?
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2answers
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How urgent is a *** System restart required *** for security?

To learn a bit of server administration I've set up a simple Ubuntu 14.04 server on which I run a personal website. I've set it to automatically install security updates, but leave out the other ...
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3answers
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Does rm -f follow symbolic links?

I have a directory like this: $ ls -l total 899166 drwxr-xr-x 12 me scicomp 324 Jan 24 13:47 data -rw-r--r-- 1 me scicomp 84188 Jan 24 13:47 lod-thin-1.000000-0.010000-0.030000.rda ...
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5answers
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How do I physically find a wifi device using a laptop or mobile phone

Okay, so I have lost my tablet somewhere in my flat and have been searching for hours already. It is an Android device, which seems to have wifi enabled (responds to pings), but doesn't seem to react ...
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6answers
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Triple (3) Monitors under Linux

I have a 3 monitor setup (each 1680x1050) via an Nvidia NVS440 (2 GPUs, 2 outputs per GPU totalling 4 outputs); this works fine under Windows XP,7 but caused considerable headaches under Linux (Ubuntu ...
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14answers
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Linux command to repeat a string n times

Is there any built-in linux command that allows to output a string that is n times an input string??
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2answers
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What does Linux do with existing files in a mount point?

If I attempt to mount a folder that already has files in it, does linux give me an error message or go ahead and show both the mounted filesystem and the files that were already in the folder?
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6answers
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How many cores I am using on a Linux Server?

I am just wondering how I can find out in bash how many CPU cores a user is now using on a Linux Server? I am submitting a fair amount of background jobs to the server, so I'd like to write a bash ...
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6answers
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/usr/local or /opt?

How do you generally proceed for your package installations on Linux, for packages that are not part of your distrib's repos? On my side I am used to install in /opt. But since, I saw this doc on the ...
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5answers
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Does running commands verbosely make them slower?

I've found myself using the -v flag for lots of applications less and less (especially for trivial stuff like tar and cp). However, when I did and I was, say, unzipping a large file, it would take ...
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6answers
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How can I diff two XML files?

On Linux, how could I generate a diff between two XML files? Ideally, I would like to be able configure it to some things strict, or loosen some things, like whitespace, or attribute order. I'll ...
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8answers
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Booting Linux off USB pendrives

Booting a Linux system off USB Pendrives is one of my favorite things. On a laptop we have the following advantages, The Harddisk can be shutdown and that reduces power consumption (hdparm) The ...
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8answers
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How do I select all text from a file with nano?

I open a file in Ubuntu nano editor from the comand line and I want to copy all the contents of the file so I can paste it in an another application outside the shell. So far I can only copy using ...
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4answers
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How to create a file which is named like a command line argument?

I was wondering how to make a file named as a flag, e.g., if I wanted to make a folder named -a, what commands would do the trick? I tried mkdir '-a', mkdir \-a, and neither worked. I'm on Ubuntu.
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3answers
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How to wget a file with correct name when redirected?

So after some time of searching on google and superuser (and scanning man pages) I was unable to find an answer to something that (I think) should be simple: If you go here: ...
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8answers
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How to set current time on Linux?

Why is the output of the following commands different? root@vmi2115:/var# hwclock Sun 26 Jun 2011 01:21:38 PM CEST -0.273230 seconds root@vmi2495:/var# date Sun Jun 26 15:21:39 CEST 2011 ...
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9answers
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How to convert Word (doc) to PDF in linux?

I have a set of files in .doc format, that need to be converted to .pdf format. I am using Ubuntu linux.
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5answers
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How to reinstall GRUB2 EFI?

After successfully updating my bios, something went wrong and I ended up with a blinking cursor on the top left corner of a black screen. No errors, no nothing. The bios now only listed a SATA: ...
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6answers
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Swap partition size for 4GB RAM

I'm planning to install Ubuntu 9.04 version. How much space should I dedicate for swap partition. I remember setting it to double the RAM size when I installed long back. At that time my RAM was 256 ...
27
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7answers
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Linux: Continuously synchronize files, one way

Scenario: An IDE is set up on a Linux desktop box, editing PHP files locally. Every time I save a file, I want this change to appear on the linux server where Apache is running. The server has ssh ...
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2answers
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What's the difference between “adduser” and “useradd”?

I wonder: Why are there these two commands on Debian Linux, with very similar names and functionality? This has always been confusing for me. Is any of them superior to another? Why aren't they ...
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4answers
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What is the different between 'locate' and 'find' in Linux?

Why there are two so similar command in Linux? and normally what are the circumstances to use each of them?
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8answers
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How to know which Linux Distribution I'm using?

How to know which Linux Distribution I'm using? uname -a gives Linux xxxxxx.net 2.6.9-42.0.3.EL.wh1smp #1 SMP Fri Aug 14 15:48:17 MDT 2009 i686 i686 i386 GNU/Linux How can I know this is ...
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2answers
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Why is it so hard to find a file in Ubuntu?

It's very hard to find files in Ubuntu. In Windows, you could just go to C:\Program Files and you would find what you need. In Ubuntu, you must use search to find something you need. Maybe I am ...
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4answers
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How do I exit an SSH connection?

I’m connecting to a server via SSH to send a message to a socket server using a command like: ssh 181.169.1.2 -p 5566 After the connection is established and I write the message and send it I ...
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7answers
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Copy directory contents using 'cp' command

How do you copy all the contents of one directory into another? For example: $ cd /home/newuser $ cp -a /backup/olduser/* . The problem with the above is that the globing pattern '*' matches the ...
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5answers
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How do I get the size of a Linux or Mac OS X directory from the command-line? [duplicate]

What command do I use to find the size of all the files (recursively) in a Linux or Mac OS X directory?
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3answers
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Why does a failed linux login take so long? [duplicate]

Possible Duplicate: Why would an incorrect password attempt take a lot longer to process than a correct one? When you get the correct login credentials, you are logged in immediately. When ...
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7answers
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How can I keep a process alive after closing the putty session?

I am using putty to interact with Linux server. I have started a process using putty. The process is running and will take 5-6 hours. I want that process to keep running after I close the putty ...
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4answers
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Delete matching files in all subdirectories

How can I remove all .swp files in all of my subdirectories under Linux?
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7answers
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Why create many partitions?

I have noticed that when installing Ubuntu some people create multiple partitions for directories. Like one for root, one for home, one for boot. What is the advantage to doing this over installing ...
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Looping Through Subdirectories and Running a Command in Each

I have a set of repositories sorted into directories based on their VCS (Git, Mercurial, SVN). With Subversion I was able to run svn update * in the parent directory and it would loop through each ...
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What's all those users in the /etc/passwd file?

The /etc/passwd is supposed to have a line for every user on the system. Amongst the common username and root there is a bunch of other users. Some examples: timidity:x:114:127:TiMidity++ MIDI ...
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10answers
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How to Remove the Last 2 Lines of a Very Large File

I have a very large file ~400G, and I need to remove the last 2 lines from it. I tried to use sed, but it ran for hours before I gave up. Is there a quick way of doing this, or am I stuck with sed?
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9answers
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How to check the health of a hard drive

My SATA drive started clicking and I was unable to access the data. It was not clicking loudly though, like a drive that has already gone bad. After tightening the connections to the hard drive, it ...
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8answers
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How to get parent PID of a given process in GNU/Linux from command line?

Resolved before asked: cat /proc/1111/status | grep PPid
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3answers
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How do I get out my embedded Windows 8 key from a Linux environment?

I have seen other SuperUser questions on this topic: How to find Windows 8 product key? | How to find Windows 8 OEM product key? However, all of the answers assume you have Windows 8 running. I've ...
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2answers
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How do I create a 1GB random file in Linux?

I am using the bash shell and would like to pipe the out of the command openssl rand -base64 1000 to the command dd such as dd if={output of openssl} of="sample.txt bs=1G count=1`. I think I can use ...
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2answers
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Can GNU Grep output a selected group?

Is it possible to use GNU grep to get a matched group from an expression? Example: echo "foo 'bar'" | grep -oE "'([^']+)'" Which would output "'bar'". But I would like to get just "bar", without ...
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1answer
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Why does deleting from the command line take significantly less time than from a GUI?

Something I wondered about as I was deleting a dozen or so images from my computer: With a quick rm -rf command on the directory's contents, all the images were gone in a snap. When I drag the same ...
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5answers
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How can I know the absolute path of a running process?

If I have multiple copies of the same app on the disk, and only one is running, as I can see with ps, how can I know the absolute path to distinguish from the others?
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recursive grep: exclude specific directories

I use recursive grep a lot to find source files with specific content. grep -Rni "myfunc" . On large codebases, this can get slow, so I use --incldue to restrict/whitelist extensions. grep -Rni ...
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2answers
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How to run a minimal Linux inside a running 64-bit Windows 7

On my previous Windows Vista laptop, I used to run Portable Ubuntu Remix for Windows, which is based on coLinux, like the similar andLinux. This worked fairly well with limited system resources (a ...
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3answers
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How accurate is `md5sum`?

When using md5sum to verify the integrity of a file, how accurate is the process? Does a verified MD5 mean that EVERY bit is exactly the same, or is there a threshold that must be broken before ...
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4answers
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How to lock a file against deletion but still make it writeable?

I want to make a file locked against deletion but still be writeable. How do I do this? The file in question is a Truecrypt volume as a file on a NAS SMB Network share, so I don't want to ...
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1answer
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Give write permissions to multiple users on a folder in Ubuntu

There is a folder that is owned by user tomcat6: drwxr-xr-x 2 tomcat6 tomcat6 69632 2011-05-06 03:43 document I want to allow another user (ruser) write permissions on document folder. The two ...
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4answers
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How to type special characters in Linux?

In windows there is possibility to type from keyboard special signs by holding alt key and typing a few numbers, that depends on with sign you want to use. Does it work with linux in the same way?
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How do I fix the Shellshock security vulnerability in debian testing/jessie?

The test command x='() { :;}; echo vulnerable' bash shows that my Debian 8 (Jessie) installation is vulnerable, even with the latest updates. Research shows that there's a patch for stable and ...