The command-line is the interactive interface to your shell.

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8
votes
3answers
957 views

How do you send command line apps directly to the background?

I already know that pressing ctrl+z stops the app, then I can send the app to background with the bg command, but that means there is a brief preiod of time that the app is stopped. How do I send the ...
7
votes
4answers
261 views

How to randomize the output from seq?

I know I can use seq to generate a random list of numbers 1, 2, 3, 4... I want to get those numbers into a random order like 3, 1, 4, 2... I know I can use shuf to shuffle the lines of a file. So I ...
7
votes
3answers
6k views

Safe way to pass password for >1 programs in bash

I'm writing a bash script, and need to ask user for his password and pass it to openssl. Whilst openssl can read the password itself, I need for two runs of the program and don't want to ask the user ...
7
votes
1answer
332 views

Is there a way to make perl -i not clobber symlinks?

A friend of mine points out that if you do: perl -pi.bak -e 's/foo/bar/' somefile when "somefile" is actually a symlink, perl does just what the docs say it will do: It does this by renaming ...
6
votes
1answer
7k views

command to zip multiple directories into individual zip files

I have a single directory that contains dozens of directories inside of it. I'm new to command line and I'm struggling to come up with a command that will zip each sub-directory into a unique ...
5
votes
2answers
806 views

Easy way to paste command line output to paste bin services?

Are there any command line tools on Linux that allow you to post output from commands or text files directly to a sharing service such as pastebin.com?
5
votes
5answers
781 views

resolve all ip addresses in command output using standard command line tools

I have several log files that contain a bunch of ip addresses. I would love to be able to pipe the data through a program that would match and resolve ip addresses. I.E. cat /var/log/somelogfile | ...
4
votes
2answers
13k views

How to display open file descriptors but not using lsof command

Hi I have read Here that lsof is not an accurate way of getting the number of File Descriptors that are currently open. He recommended to use this command instead cat /proc/sys/fs/file-nr While ...
3
votes
7answers
444 views

Batch renaming of files [duplicate]

I have a directory full of images: DSCN4749.JPG DSCN4750.JPG DSCN4892.JPG ... And I would like a one-liner to rename them to (say). dscn4749.jpg dscn4750.jpg dscn4892.jpg ... How do I do this? ...
3
votes
2answers
391 views

I need help with a cronjob to watch for runaway processes and kill them

I have an interesting situation, I have a runaway ruby process - I know exactly how I trigger it. Point is, it got me thinking about runaway processes (CPU usage or memory usage). How would one ...
2
votes
1answer
132 views

cat file to multicast

I have a text file (test.txt) which represents captured network data. The actual protocol is text-based, with NULL line endings, so this isn't a problem. I need to run this test captured data ...
2
votes
1answer
242 views

Simpler processing of shell script options

I'm looking for way to process shell script arguments that is cleaner and more "self documenting" than getopt/getopts. It would need to provide... Full support of long options with or without a ...
2
votes
2answers
10k views

No network connection in CentOS 6.3 Minimal under VMWare Player

I'm trying to replicate in VMWare Player the exact same conditions I have under my Dedicated Server for testing purposes. Now, the thing is that that when I try to install something, or ping ...
20
votes
4answers
785 views

Are Linux utilities smart when running piped commands?

I was just running a few commands in a terminal and I started wondering, does Unix/Linux take shortcuts when running piped commands? For example, let's say I have a file with one million lines, the ...
15
votes
4answers
10k views

Usage of dash (-) in place of a filename

For a command, if using - as an argument in place of a file name will mean STDIN or STDOUT. But in this example, it creates a file with the name -: echo hello > - How can I make - in this ...
14
votes
3answers
2k views

Why isn't there any shell command to create files?

Attention please: I am not asking how to make a file from the command line! I have been using touch for making files for years without paying attention that its main purpose is something else. If ...
13
votes
1answer
5k views

How do I find the window dimensions and position accurately?

I've been trying to figure out the size of a window for use in a small script. My current technique is using wmctrl -lG to find out the dimensions. However, the problem is this: The x and y figures ...
11
votes
5answers
13k views

Linux ls to show only filename date and size

How can I use ls in linux to get a listing of filenames date and size only. I don't need to see the other info such as owner or permission. Is this possible?
10
votes
2answers
2k views

IP to Country console command

Is there a console command that takes an IP address as an input and shows its geographical information like city, country, ISP, etc.?
9
votes
10answers
7k views

How can I “cat” a file and remove commented lines?

I'd like to know if there is a way that I could cat file like php.ini and remove all lines starting with ; For example, if the file contained this: ; - Show all errors, except for notices ; ...
8
votes
5answers
472 views

What's the best way to take a segment out of a text file?

What's a good way of extracting say, lines 20 -45 out of a huge text file. Non-interactively of course!
7
votes
5answers
1k views

Read and confirm shell script before piping from curl to sh (curl -s [url] | sh)

Whenever I have to execute a shell script from the web curl -s [url] | sh, I first open url in my web browser to make sure the script isn't malicious and is safe to run. I remember seeing a command ...
7
votes
2answers
1k views

Directory “diff”?

I have two directories which are different versions of the same software package. I'd like to list all the files/directories that have changed between the two then copy those differences to a new ...
6
votes
1answer
1k views

How to mount a Truecrypt container with a timeout from the command line?

I'm mounting a truecrypt container via the command line (i.e. truecrypt file dir). Is there any way to have truecrypt automatically unmount the container after a given amount of inactivity in dir?
5
votes
3answers
4k views

How to bring up a wi-fi interface from a command line?

I can't figure out how to properly bring up the wi-fi card on my laptop. When I turn it on and issue $ sudo iwconfig wlan0 txpower auto $ sudo iwlist wlan0 scan wlan0 Interface doesn't support ...
5
votes
2answers
805 views

A command line utility to visualize how fast a file is growing?

I want to grok how fast a particular file is growing. I could do watch ls -l file And deduce this information from the rate of change. Is there something similar that would directly output the ...
5
votes
2answers
77 views

Handling an option-like filename in the shell [duplicate]

Possible Duplicate: How do I delete a file whose name begins with "--"? Due to mismatched switches when I was trying to run a command, I have a log file named -w in a directory. I ...
4
votes
1answer
222 views

Executing a remote command on SSH connection, before login

I am trying to find a way to execute a specific command when connecting to a server via SSH. By this I mean, the command will execute unconditionally on opening a connection, so this would preferably ...
4
votes
1answer
363 views

Is there a command such as xwininfo, xdpyinfo, xprop, or xlsclient that will tell me what font an X client window is using?

I'm trying to find a command that will report what font a given X window is configured to use. Does such a command exist? Looking through these tools I did not see an option that would give me this: ...
4
votes
1answer
63 views

How can I get information about my virtual desktops via the command line?

I'm curious how I can get information such as the dimensions of my desktop, which desktop is currently active, and what labels (if any) are set for my desktop enviornment (DE).
4
votes
1answer
62 views

Computing the visible area of a partly hidden window

I have to (scriptly) take screenshots of windows, some of which may be partially or fully hidden by other windows. Of course, in such a case the screenshot is useless, and I'd rather print a warning. ...
4
votes
2answers
397 views

Is there a way to simulate a “Close” event on various windows using the terminal?

I answered on Ask Ubuntu Quit all instances of gnome-terminal via a command but as you all can read gnome-terminal didn't seems to have a SIGcall I could use to simulate this "Close" event. So this ...
4
votes
2answers
149 views

Is it possible to restrict certain commands from being run in a directory?

I have two directories: src and projects. I would like to prevent myself from running git ... unless I am specifically inside src or projects. Is this possible?
4
votes
3answers
246 views

Commandline global proxy program?

I'm living in China, and lots of web service is not available or stable here like Github/Bitbucket/Imgur, When I'm using wget, git or some other commandline tools, I need using a proxy. Is there any ...
4
votes
2answers
1k views

Is there any command-line, generic HTTP proxy (like Squid)?

I can easily use Netcat (or, Socat) to capture traffic between my browser and a specific host:port. But for Linux, does there exist any command-line counterpart of a Squid-like HTTP proxy that I can ...
4
votes
2answers
2k views

pdf viewer for command line only

Is it possible to view pdf documents without having gdm (or similar) running? Rationale: I'm working on a remote server (assume no X forwarding) processing some data, creating some plots (assume pdf ...
4
votes
4answers
415 views

ls command operating differently depending on recipient

How does commands like ls know what its stdout is? It seems ls is operating different depending on what the target stdout is. For example if I do: ls /home/matt/tmp the result is: a.txt b.txt ...
4
votes
2answers
1k views

How to prevent my screens from dimming (going black) from the command line

In KDE, there was a system setting where you could specifically set the monitors to never go black. Now I've switched to dwm and (it might not be related) my screens dim after about 10 minutes. How ...
3
votes
1answer
86 views

Getting size of directories and exclude some folders

I have an directory structure like this: application1 application1_edit application2 application2_edit Is there any way to get the total size for every folder (including sub-directories) and ...
3
votes
3answers
281 views

What is a “non-option argument”?

I am trying to understand info who but completly fail at the term »non-option argument«. Can someone please explain this term to me in simple words or an example? UPDATE: from ' info who' ...
3
votes
4answers
6k views

Move all files with a certain extension from multiple subdirectories into one directory

Suppose I have a bunch of zip files in several directories: Fol1/Fol2 Fol3 Fol4/Fol5 And I want to move them all to a common base folder. How would I do this?
3
votes
2answers
2k views

Obtain .avi file info from command line

What is the best way to obtain information as bitrate, framerate, width/height of an movie file (in my case .avi) from the command line? I am looking for a basic tool that works similarly as ...
3
votes
2answers
2k views

How to refresh a window by terminal? Or how to simulate `F5`?

I would like a way to refresh a specific window by the terminal. Probably I will need a comand to find the id or the name of the window and a command to refresh it. It looks like xrefresh cannot do ...
3
votes
1answer
9k views

Command to install linux headers fails

I need to install my linux headers for an Nvidia driver install. But I get an error when doing so: peter@peter-deb:~$ sudo apt-get install linux-headers-$(uname -r) Reading package lists... Done ...
3
votes
1answer
277 views

Could someone please explain some of these escape codes?

I'm seeing this in my .bashrc file: PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\ [\033[01;34m\]\w\[\033[00m\]\$ ' and I have absolutely no idea what all those ...
3
votes
2answers
3k views

su vs su - (on Debian): why is PATH the same?

I know what should be the difference between su and su -, but in my system (debian testing) for example PATH is the same: [root]# su [root]# echo $PATH ...
2
votes
3answers
196 views

What command do I use to see the start and end block of a file in the file system?

Is there any command that will output the beginning and ending blocks of any file?
2
votes
3answers
269 views

Trying to send HTML mail on mac OSX Mountain Lion

I'm trying to send email with an html file as the body (it's actually a cucumber results report if that matters) or an attachment (if sending it as the body does not work) via the command line I've ...
2
votes
2answers
486 views

Can one copy a relpath in one command?

I find myself doing this often enough that I wonder if there's a standard Unix way to do it: % mkdir -p /TARGETDIR/relative/path/to % cp ./relative/path/to/somefile /TARGETDIR/relative/path/to In ...
2
votes
2answers
894 views

Concatenate multiple files under subdirectories

My directory structure is given below x:\Project_2012-158A\Sample_4041 SampleSheet.csv 4041_CGTACG_L002_R1_001.fastq 4041_CGTACG_L002_R2_001.fastq 4041_CGTACG_L006_R2_001.fastq ...