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Questions tagged [linux]

Linux is the generic term for a UNIX-like open source operating system based on the Linux kernel.

GNU/Linux is a UNIX-like Open Source operating system. Linus Torvalds originally wrote the Linux kernel with contributions from others on the MINIX usenet board. Since then, Linux had thousands of developers, both paid by companies and volunteers. The main system tools and libraries for GNU/Linux are sourced from the GNU Project, hence the nomenclature GNU/Linux (GNU Toolchain over Linux Kernel). The Linux kernel is licensed under the GPL v2 license.

There are many different Linux Distributions (sometimes shortened to distro), which consist of software applications packaged and provided with the Linux kernel, being Slackware the oldest active distro and Debian, Red Hat and CentOS among the most used on Internet servers¹.

The Linux kernel is commonly run on servers but is highly portable and is used in a variety of applications, from wireless routers and cell phones to clusters and super computers with thousands of nodes and processors.

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How to check if an RSA public / private key pair match

I have two files, id_rsa and id_rsa.pub. What command can be used to validate if they are a valid pair?
Ryan
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Job scheduling using crontab, what will happen when computer is shutdown during that time?

I schedule some tasks using crontab. What will happen if my computer is shutdown or turned off during the time when cron was scheduled to do something? Does each missed cron job run after computer is turned on, or are missed jobs for that day…
seg.server.fault
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Keeping a linux process running after I logout

I'm connecting to a Linux machine through SSH, and I'm trying to run a heavy bash script that makes filesystem operations. It's expected to keep running for hours, but I cannot leave the SSH session open because of internet connections issues I…
doc_id
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Meaning of directories on Unix and Unix like systems

I've been using Linux for a couple of years now but I still haven't figured out what the origin or meaning of some the directory names are on Unix and Unix like systems. E.g. what does etc stand for or var? Where does the opt name come from? And…
Luke
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best way to clear all iptables rules

I currently have this snippet: # flush all chains iptables -F iptables -t nat -F iptables -t mangle -F # delete all chains iptables -X Is there a possibility that some impervious rule will stay alive after running this? The idea is to have a…
kagali-san
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Is it possible to make Nginx listen to different ports?

I created one Nginx with one Linux Azure VM, is it possible to make nginx listen to different ports so that when I change the port number, the content would be different. I found there would be a collision if I created two or more ports related to…
billcyz
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How can I port forward with iptables?

I want connections coming in on ppp0 on port 8001 to be routed to 192.168.1.200 on eth0 on port 8080. I've got these two rules -A PREROUTING -p tcp -m tcp --dport 8001 -j DNAT --to-destination 192.168.1.200:8080 -A FORWARD -m state -p tcp -d…
Stu
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Find out symbolic link target via command line

Say that I setup a symbolic link: ln -s /root/Public/mytextfile.txt /root/Public/myothertextfile.txt is there a way to see what the target of myothertextfile.txt is using the command line?
Jared
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How can I verify if TLS 1.2 is supported on a remote web server from the RHEL/CentOS shell?

I'm on CentOS 5.9. I'd like to determine from the linux shell if a remote web server specifically supports TLS 1.2 (as opposed to TLS 1.0). Is there an easy way to check for that? I'm not seeing a related option on openssl but perhaps I'm…
Mike B
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What useful things can one add to one's .bashrc?

Is there anything that you can't live without and will make my life SO much easier? Here are some that I use ('diskspace' & 'folders' are particularly handy). # some more ls aliases alias ll='ls -alh' alias la='ls -A' alias l='ls -CFlh' alias…
Gareth
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How to handle security updates within Docker containers?

When deploying applications onto servers, there is typically a separation between what the application bundles with itself and what it expects from the platform (operating system and installed packages) to provide. One point of this is that the…
Markus Miller
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How do you make it obvious you are on a production system?

A few of us at my company have root access on production servers. We are looking for a good way to make it exceedingly clear when we have ssh'd in. A few ideas we have had are: Bright red prompt Answer a riddle before getting a shell Type a random…
Sionide21
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How to list Apache enabled modules?

Is there a command that list all enabled Apache modules?
supercobra
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How to forcibly close a socket in TIME_WAIT?

I run a particular program on linux which sometimes crashes. If you open it quickly after that, it listens on socket 49201 instead of 49200 as it did the first time. netstat reveals that 49200 is in a TIME_WAIT state. Is there a program you can…
Rehan
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how do you create an ssh key for another user?

I'm trying to create an ssh key for another user. I'm logged in as root. Can I just edit the files generated by ssh-keygen and change root to the user I want?
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