Most voted "linux" questions
For SOFTWARE DEVELOPMENT issues that are specific to the GNU/Linux operating system. Mere use of shell and desktop, installation and support are not within the scope of the site. If your question is not about development or development but has nothing to do with Linux Apis or Linux-specific behavior you should not use this tag, even if you are running on Linux.
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28
votes6
answers1852
viewsC programming for ARM
I’ll start a project in C that will have as target a plaque Colibri T20, processor-equipped NVIDIA Tegra 2 ARM, running a light version of Linux. I wonder if, in addition to having to use a cross…
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24
votes3
answers739
viewsWhat does ":-!!" mean in C language?
In a Linux kernel library, specifically this: /usr/include/linux/kernel. h, there’s a macro with a code strange to me: /* Force a compilation error if condition is true, but also produce a result…
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votes1
answer29792
viewsSet up Cronjob to run every 5 minutes, when it’s between 5 to 20 hours
I need to make a configuration so that mine cronjob function every 5 minutes. However, if the time of day is before 5and greater than 20 I don’t want you to spin. I mean, I want a make one cron…
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20
votes4
answers8186
viewsHow to schedule a recurring task on linux?
What command can I use to schedule a recurring task on linux? I would also like to send the return of the command by email automatically. What is the most suitable tool?
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20
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answer1007
viewsWhat programming languages support Linux and Windows?
The question is already in the title, however to make it clearer: What languages I write a single code in, and run on both Linux and Windows? Example C. Except some commands like system("cls");…
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19
votes2
answers468
viewsMeaning of "__"
In the implementation of the Linux kernel, I came across this statement on line 89: #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; }) I know that in C, symbols…
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15
votes4
answers1418
viewsHow do I programmatically respond to a command on the Linux terminal?
I have a Python script that runs a certain command on the system. This command expects a password to be typed right away, the only way it works is this, it is not possible to pass the password via…
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15
votes4
answers309
viewsHow to deal with a comet process?
Analyzing the linux API I noticed that an interesting structure is possible: #include <unistd.h> #include <stdlib.h> int main() { while (1) { if (fork()) exit(0); // Altera meu pid…
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14
votes2
answers4380
viewsLinux C programming - IDE vs. editor + command line
I’ve been looking for a similar question here and I haven’t found anything so if you’ve already answered I’m sorry. I’m a beginner in C programming and would like to know if it is more appropriate…
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14
votes1
answer268
viewsWhat happens to a 2:30 Cronjob if the server goes down at 2:28 and only comes back 5 minutes later?
I don’t know if the question is confusing, but is that I have used a lot of Cronjob in my systems currently and do not want to have problems. So I’m going to illustrate my concern with a…
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13
votes3
answers5462
viewsWhat is the lifespan of an SD card with Raspbian (Raspberry Pi)?
As all Raspberry Pi users should know, operating system runs from SD card. This can result in a problem, because if the card is written many times constantly, it will reduce SD lifespan for quite…
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12
votes3
answers611
viewsHow to ensure that a service is always running on Centos?
I created a startup script for my application in Centos, so I can use the commands below to initialize/stop the application: service django_app start service django_app stop How do I ensure this…
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12
votes1
answer129
viewsHow to extract the path to the file
In a variable that contains the path to a file and its name, the file name can be extracted as follows: #!/bin/bash filenamepath="/caminho/para/ficheiro.pdf" filename=$(basename $filenamepath) Which…
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11
votes2
answers4325
viewsPermission denied when moving file with move_upload_file on Linux server
I’m trying to use the move_upload_file to move a file sent by the user to its final destination: $pasta = '../../public_html/admin/helpdesk/ticket/uploads/'; if (!empty($_FILES['img']['name'])) {…
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11
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answer28571
viewsEnable . htaccess in Ubuntu
I’m using the Ubuntu system on my PC and my apache doesn’t seem to recognize htaccess, none, because I created one. htaccess to my project only that it does not interpret what is in the content. The…
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11
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answer12600
viewsHow to remove python-installed packages
downloaded a package with wget, unzipped and downloaded the folder, used the command: python setup.py install It ran without errors, but now I no longer use this program, what is the correct way to…
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11
votes1
answer152
viewsConvert PDF document pages to Jpgs
The following code is working within the desired, where it receives parameters in order to convert all pages of a PDF file into JPG files: ID (natural number) Absolute path (must exist and point to…
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11
votes2
answers1867
viewsDifference between VM and LXC Containers
Hello, I am looking to understand what is the difference between VM and LXC Containers? Everything I read sounds a little abstract and the end result seems to be the same.
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11
votes1
answer2988
viewsWhat is the purpose of the "/dev/null" path in some commands?
Many times, I have seen some people teaching to do some commands (mainly related to text outputs or things like), where is used this directory or file called /dev/null. Example: wget -qO- $url…
linuxasked 8 years, 9 months ago Wallace Maxters 102,340 -
11
votes1
answer262
viewsHow do I change the language of Git to English on Linux?
I’m using Git on the Linux terminal (Ubuntu), and it’s in English. In the master business Initial submission. nothing to send (create/copy files and use "git add" to register) How I can change Git…
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10
votes2
answers636
viewsWhy does linux have an ISO for each processor architecture?
Hello, I would like to understand why Linux has several ISO's for each type of CPU (AMD64, i386, etc.), because Windows does not need it, and how is compiled for each type of architecture. If…
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10
votes1
answer896
viewsWhat is MUSL? What are the pros of someone carrying it on my laptop?
I’m interested in the pros that this can bring to my laptop.
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9
votes5
answers7529
viewsHow to search recursively using grep
How to search for a given word recursively in all files in the current directory and its subdirectories? I tried to travel with: find . | grep "palavra"
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9
votes2
answers295
viewsOpencv haartraining - Out of memory
I have 30 positive images and 60 negative images. When I tried to run haartraining with 4GB of memory and Quadcore processor, I get this error message: OpenCV ERROR: Insufficient memory (Out of…
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9
votes2
answers598
viewsGit workflow (workflow) using Github?
I need to learn how to clone a project from github to my local computer and, after making the necessary changes, send the modifications back to the remote project. Basically the workflow git by…
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9
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answer16141
viewsCMD, Powershell, Bash - What’s the difference?
There are differences between them, which? I’m talking about Ubuntu’s Bash. I’m curious because to me they seem to do the same thing!
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9
votes1
answer1094
viewsHow to read stdin in python?
Using the netcat to monitor a particular port on my device, using the shell command terminal, I can check the data received by it and send data back to the connected device, as for example, makes a…
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9
votes1
answer95
viewsWhat do the terms Memory Poisoning and HWPOISON mean?
I’m studying some things in the kernel GNU/Linux and found the above terms in the Memory Management/ Memory Allocation, would like to know the meaning of both and what they are ?…
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8
votes3
answers784
viewsSet the threads priority in C++11
In the program I’m developing I have two Std::threads that are always active throughout the life of the program. However, I consider that the role of one of them is of minor importance and would…
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8
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answer426
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answers32009
viewsWhat is the most complete linux for programmers?
I study programming by hobby about 4 years ago, I started with php, c#, I learned a little bit about everything, but now I’m thinking about going deeper. I’ve always used Windows that I’ve always…
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8
votes3
answers9428
viewsHow does serial communication work and how do I use C/C++?
I use the Debian 7.1 and need to make serial communication between a computer and a microcontroller using C/C++. I’ve done a lot of research on the subject, but the articles and examples I found are…
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8
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answers1617
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answers143
viewsDoubt with PHP and Apache
I formatted my machine and was advised to use Linux, and I did so. But in my localhost, the files .php are not read/recognized, only files .html. I installed, reinstalled and did everything I saw on…
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8
votes1
answer1407
viewsDifferences between one: Linux and Windows Development Environment
I would like to know the development differences between these two Sos. I have little knowledge about Linux, only theoretical. Today, researching about creating a PHP environment, without using…
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8
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answers19310
viewsAlternatives for developing in C# on Linux?
My notebook has installed the Ubuntu 14 operating system. I have great desire to enter the development in the language Csharp. But I wonder if there is a good alternative in OS like Linux, since it…
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8
votes3
answers537
viewsHow to remove the space of "4 980 Raphael" only between numbers
I have a string "4 980 Rafael" and I would like to know how I will remove only the spacing that are between the numbers in shell script.
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8
votes1
answer794
viewsPermission PHP file
I have a file PHP inside the Linux opt directory. Inside it I have a script with queries to update a database, with password and login connection of the database. This file is set inside a bash file…
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8
votes1
answer97
viewsLinux Shell Script - Difference between $(()) and (())
I’m studying shell script and learned to use $(()) and (()) to make calculations. I understood the difference: while $(()) serves to make a calculation and return the result of it, (()) serves to…
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7
votes3
answers6510
viewsHow to access a server via SSH without using password?
I have to connect a Linux server via SSH, using Putty as a client, many times a day and every time I need to put user and password. I have seen a person performing connection without using user and…
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7
votes4
answers59952
viewsCopy files via SSH between two remote servers
How to copy files from Servier1 to servor2 via SSH with only one command line, and I am not logged in to any of them? I’m on a third machine. And I have the credentials of both.
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7
votes2
answers2210
viewsPHP on linux or windows
Explanation: I know it’s a controversial question, but I’m not an old man of programming and I have knowledge of linux, but I never chose it because I use C# from time to time and in my college they…
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7
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answers133
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7
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answers339
viewsBash - Mysql backups
I rode the script below, to perform backups of three Mysql bases. I would like to know if it is correct. #VARIAVEIS DATE=`date +%Y%m%d-%H%M` HOSTNAME1="xxxxx" HOSTNAME2="yyyyy" HOSTNAME3="zzzzz"…
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7
votes1
answer138
viewsTomcat on Windows and Linux
I currently have a server Tomcat running on a machine with Windows Server 2012. But I got some tips from some friends from Infra where they say the Tomcat in the Linux has better performance. So I…
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7
votes2
answers2142
viewsDifference between /dev/urandom and /dev/Random
I recently read a post on the oracle jdbc driver, talking about making the following configuration on jvm running on Linux: -Djava.security.egd=file:/dev/../dev/urandom According to the reference,…
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7
votes1
answer154
viewsHow is the process of installing the letsencrypt.org certificate on Linux on Apache servers?
I really liked the idea of using the certificate from letsencrypt.org. I found several tutorials on the internet, including that in Digital Ocean. All the steps worked correctly, but since I don’t…
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7
votes1
answer9516
viewsHow to change the version of PHP in which Composer runs on Linux?
I installed Composer on my Ubuntu via the following command: apt-get install composer Ubuntu currently supports multiple installed PHP versions. I have PHP5.6, PHP7.0 and PHP7.1 installed on my…
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7
votes1
answer6958
viewsWhat would be a PID?
I’m starting to study desktop applications. I had a certain question about how I could know if a particular application is running and I was told that I could use the PID, as a solution, to detect…
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7
votes2
answers3359
viewsDifference between "~" tilde and "/" bar at linux prompt?
I am starting a lower level part, where I will program the part of users, permissions and etc. My first question is ~ and / at the prompt ?