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

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36
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3answers
11k views

In Linux, how do I truncate command-line output?

If I grep -nr sumthin * in my source code directory, it also spews out very long lines from minified JavaScript or CSS files. I want to get just the first 80 characters per line. For example, a ...
36
votes
6answers
25k views

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 ...
36
votes
3answers
18k 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, ...
36
votes
3answers
17k views

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 ...
35
votes
3answers
37k views

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: ...
35
votes
4answers
86k views

mount dev, proc, sys in a chroot environment?

I'm trying to create a Linux image with custom picked packages.What I'm trying to do is to hand craft the packages I'm going to use on an XO laptop, because compiling packages takes really long time ...
35
votes
5answers
20k views

How do I configure SSH so it dosen't try all the identity files automatically?

I have been putting my ssh identity files inside my ~/.ssh/ folder. I have probably about 30 files in there. When I connect to servers, i will specify the identity file to use, with something like ...
35
votes
8answers
8k views

How do you track which packages were installed on Ubuntu (Linux)?

(This question is very similar to 10458. It was suggested that Fedora and Ubuntu/Debian are different enough to warrant different answers.) As I use any Ubuntu setup I gradually install a number of ...
35
votes
4answers
3k 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
12answers
4k 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... ...
34
votes
2answers
22k views

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?
34
votes
14answers
41k views

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??
34
votes
14answers
17k views

What is Gnome / KDE etc?

I have been on Windows my entire life. Without getting too technical, what are these things? When I search on the net, I get some technical results. I simple do not understand what these things are! ...
34
votes
5answers
61k views

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?
34
votes
2answers
4k views

How come one user can delete another user's 755 files?

I have a backup upload script that scp’s files to another server using the user upload. Another script on the target server then chown’s these to another user and sets the file mode to 755. If I then ...
34
votes
4answers
24k views

In vim, how can I quickly switch between tabs?

In gnome-terminal, I can just press Alt + (1, 2, 3, etc.) to switch to specific tabs. I can also use Ctrl + (PgUp / PgDn) to cycle through tabs (admittedly less convenient, but it can be remapped). ...
34
votes
3answers
100k views

How does one change user's home directory in Ubuntu 9.04?

Does anyone know how I might change my home directory in the shell please?
34
votes
6answers
16k views

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 ...
34
votes
6answers
67k views

Bash script to delete files older than x days with subdirectories

I'm trying to delete a ton of files older than x days. Now I have a script to do that find /path/to/files* -mtime +10 -exec rm {} \; But this will also delete the subdirectories. There are a ton ...
34
votes
6answers
2k views

A more comfortable way to edit a long $PATH?

I want to add, in ~/.bashrc, a few directories to my $PATH. My $PATH is quite long so it's a bit hard to see what directories it contains and in what order. I know I can modify my ~/.bashrc to be: ...
34
votes
1answer
39k views

Show only current directory name (not full path) on bash prompt

The way my bash prompt is currently configured, it shows the whole path to the current directory. This is annoying when I'm deep inside a directory tree, as the prompt becomes so long that every ...
34
votes
3answers
88k views

How to create a bootable USB from a bootable ISO with the command line on Linux?

I have a CD that's created from an ISO file which I use to install a custom version of Ubuntu via plop linux. The cd works fine but I'd like to use a bootable USB drive instead. I used the command dd ...
33
votes
3answers
4k views

Have a file named ~ (tilde) in my home-directory

I just noticed that I have a file called ~ in my ~-directory. $ ls -la ~ ... -rw-r----- 1 x1 x1 733962240 Mar 1 17:55 ~ ... Any idea how I can mv or rm it?
33
votes
7answers
40k views

ls -d is not displaying directories. Is there a way to get ls to only display directories instead of files and directories

Is there a way to get ls to only display directories instead of files and directories From the man page. -d, --directory list directory entries instead of contents, and do not ...
33
votes
6answers
30k views

Uploading files to S3 account from linux command prompt

I've got several large files sitting in my linux hosted account that I need to upload to my S3 account. I dont want to download them first and then upload it into S3. Is there any way I can "upload" ...
33
votes
5answers
127k views

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: ...
33
votes
7answers
28k views

How can I find the oldest file in a directory tree

I'm looking for a shell one-liner to find the oldest file in a directory tree.
33
votes
2answers
88k views

How can I clear the IP address of Ethernet interface without cycling the interface up/down or restarting it

What is the Linux command to clear IP address of an interface without bringing it down and/or restarting network services. Seems strange ifconfig is able to change IP address but has no option to ...
33
votes
5answers
35k views

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 ...
33
votes
5answers
10k views

Two keyboards on one computer. When I write with A I want a US keyboard layout, when I use B I want Swedish. Possible?

I have a laptop which I use an external keyboard with. When I type using the external keyboard I want to use a US keyboard layout, since that's the type of external keyboard I have. On the other hand, ...
33
votes
2answers
5k views

Is it possible to compile a Darwin Distro from source, like you can a build a Linux Distro?

I have read through and undertaken Linux From Scratch (and BLFS) and I was wondering, can I follow this guide to create a Darwin Distro by substituting the xnu kernel? Would the process be vastly ...
32
votes
6answers
76k views

play mp3 or wav file via Linux command line

I would like to make an alarm system backed by a Ubuntu (no graphical interface) box, which plays various announcement and alarm audio tracks (.mp3 or .wav) via the command line. For example: $ ...
32
votes
2answers
32k views

List files bigger than filesize specified

How can I make ls (or any other particular command) to list me only files bigger than a specific file size?
32
votes
4answers
37k views

Find all files on server with 777 permissions

I'm looking for a Linux command to go through all the directories on my server and find all files with 777 permission. The output would be a list of all those files with full path.
32
votes
3answers
28k views

How to join/merge many mp3 files?

Searching Google on how to join/merge many mp3 files, it suggests that I should just cat them together. That might "work", but clearly it is not the correct way to do it, as each header and set of ...
32
votes
6answers
45k views

How can I view results of my cron jobs?

I see so many guides on how to run crontab, but what I need right now is to learn how to Find log files about cron jobs Configure what gets logged
32
votes
5answers
102k views

How to access a BitLocker-encrypted drive in Linux?

I have a laptop running Windows 7 Ultimate. I have encrypted my drives using BitLocker. Now I have also installed Lubuntu along with Windows. But my encrypted drives are not visible in Linux. How ...
32
votes
3answers
3k views

Can history files be unified in bash?

I routinely run multiple screen sessions on my Linux desktops and servers. A problem with this is that when I grep through my command history, I find I issued a command in a different session, and ...
32
votes
2answers
91k views

What do ALSA devices like “hw:0,0” mean? How do I figure out which to use?

I've searched over and over and can't find any explanation of what "hw:0,0" means. How do I determine the number of my USB audio card? MPD requires me to enter something like this: audio_output { ...
32
votes
3answers
14k views

Bad font anti-aliasing in Ubuntu

I'm switching from Fedora 8 to Ubuntu 9.04, and I can't seem to get it to get a good font anti-aliasing to work. It seems that Ubuntu's fontconfig tries to keep characters in integral pixel widths. ...
32
votes
8answers
7k views

Is flash drive wear a significant issue?

My netbook has a flash drive instead of a hard disk drive, and I'm using Ubuntu Netbook Remix with ext3 as the file system. I've read some articles concerning flash drive wear, and the main concerns ...
31
votes
7answers
64k views

Which is more efficient - tar or zip compression? What is the difference between tar and zip?

I'm working in Linux environment and want to know about tar and zip commands. Which is more efficient - tar or zip? I also need to know the differences between the tar and zip commands. Can anyone ...
31
votes
10answers
3k views

Prevent user typing accidental space between rm and wildcard

Intention: rm -rf string* Problem: rm -rf string * The first case is a legitimate and common use of rm, a small typo can cause a lot of problems in the second case. Is there a simple way to ...
31
votes
2answers
58k views

Updating Time : ntpdate[3108]: the NTP socket is in use, exiting

The time on my system is incorrect for some reason. i need to run an update but i can't seem to be able to this is the errror. ntpdate pool.ntp.org 31 Aug 12:31:59 ntpdate[3108]: the NTP socket is in ...
31
votes
8answers
17k views

Swap partition size on a 64 GB RAM computer for memory-intensive work

I have 64 GB RAM and 240 GB SSD on my computer, which I'm going to use for memory-intensive calculations (machine learning, data mining, etc.). Most of the advice I found on the Internet are ...
31
votes
8answers
50k views

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 ...
31
votes
4answers
48k views

yum install gcc-g++ doesn't work anymore in CentOs 6.4

Today installed CentOs 6.4 fresh new on my workstation. I wanted to install g++. With my surprise I didn't succeed by using yum install gcc-g++ The thing is that even by doing a search I don't ...
31
votes
4answers
29k views

How do I find out what processes are accessing the hard disk in a GNU/Linux-based system?

I'm looking for the equivalent to top for disk access, so I can tell which process(es) are currently reading and/or writing to disk. I'm currently using Ubuntu, but I imagine there's a standard tool ...
31
votes
5answers
49k views

Good block size for disk-cloning with diskdump (dd)

I use dd in its simplest form to clone a hard drive: dd if=INPUT of=OUTPUT However, I read in the manpage that dd knows a blocksize parameter. Is there an optimal value for the blocksize parameter ...
31
votes
3answers
12k views

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 ...