How can I calculate the percentage of RGB values in an image using Linux? I’ve done some research and it appears that C# and Python may be the way to go. Answer Let ImageMagick generate a histogram for you showing how many pixels there are of each colour, So, say you have have an image called image.jpg,…
Tag: linux
Why does a Perl script run during boot on CentOS not find certain modules?
I am currently trying to run a perl script at boot in a custom version of CENTOS. I am doing so by calling it from an rc1 script, the call looks like this: But I’m getting the error “Can’t locate strict.pm in @INC” This isn’t specific to strict.pm, it throws that error at for whi…
JBOSS_HOME is not properly being set in Linux, System.getenv from Eclipse returns null
I’ve added JBOSS_HOME both in Linux and Windows. Here is my arquillian.xml http://jboss.org/schema/arquillian/arquillian_1_0.xsd”> In windows tests are running fine but in Linux I’m getting following exception: NullPointerException due to jbossHome variable being null in ManagedDeployable…
Bash – one-liner echo with delimiter
So my sample code so far looks like this: I want to be able to echo it out to make it look like the following: But the problem is that when I tried using AWK, sed, or IFS they also use n as delimiters which I don’t want that to happen as the text gets all messed up. Is there
How does the kernel handle a read operation on proc files when several instances of the same driver are running simultaneously
I have a question regarding the way proc files are handled when several instances of the same driver are running simultaneously. lets assume that a my system runs a couple of instances of the same driver simultaneously, but only one of them (according to some inner decision making) created a proc file and mai…
Daemonize a perl script at startup Linux
I have a custom version of CENTOS that I need to run a perl script as a daemon in at all times. To do this I want to get it to run on startup as a daemon. When the machine is on I can daemonize the script with the command And this works fine. So I have an rc1 script
SED one liner to uncomment and replace first occurrence of a pattern
I have this settings.conf file in linux defined as follows: I would like to uncomment # second-setting = off of Section A only (first occurrence), and set the value to on. So far, I have this: cat settings.conf | sed ‘/^# second.*/ {s/^#//;s/off/on/}’ Any tips? Answer Is this what you had in mind?…
How does tmux, vim, emacs, etc transcend the UI limitations of *nix terminals?
When I’m writing a program for use on the command line, I notice that there’s some limitations. For instance, I can’t draw a 1-pixel-thick horizontal or vertical line like tmux does when it separates panes in a window. I can only move the cursor down, not up like VI seemingly does. I canR…
Fabric Remote Execution requiring a user response from a prompt?
I would like to handle when a fabric script requires a response. Eg. Apply the above migration? (yes|no) [no]: The fab function that creates this prompt: local(“php root/protected/yiic.php migrate”) Answer Try to disable interactive mode during running command: From docs: interactive: boolean, spe…
IndentationError in python script for organising Music
I have made this script in the past and I want to use it now, but an error occurs when trying to run it. This script is about organising my music. I have a directory organised by label and want to grab the artist name from the directory names inside label and year directory and create new directories inside t…