Xen: VM failed to boot

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Question: Hello, I am using Xen on Centos 7 and it was working fine from last 3 years. After I reboot the VM I am getting below error: “dracut-initqueue[270]: Warning: dracut-initqueue timeout – starting timeout scripts” “[ 195.426203] dracut-initqueue[270]: Warning: Could not boot. [ 195.435712] dracut-initqueue[270]: Warning: /dev/centos_static/root does not exist [ 195.436499] dracut-initqueue[270]: Warning:
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How to mirror a website using wget on Linux?

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How to mirror a website using wget on Linux? If the command can filter only specific file extensions, such as pdf and docx, it will be much better too. To download all PDF files from https://example.org/path/ as an example, you may use this command: wget –mirror \ –convert-links –no-parent –quiet \ –adjust-extension -A pdf \
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5 necessary PC hardware that a programmer needs to upgrade

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The world of technology has evolved drastically over the last few decades. Almost every aspect of our lives is dominated by technology. At the heart of technology lies computer programming. Computer programming is what dictates the success of the technology. I mean think about it, your smartphone, PC, ETC they all rely on programming. This
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New Linux Kernel 5.0: Features and Improvements

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Linux is the most used and well-known open-source operating system for computers, mobile devices, servers, and mainframes, etc. Linux has so many awesome features to serve its users like Live CD/USB. And it is fast, easy and free to use by computers around the world. The kernel is referred to as the essential component of
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How to do screen recording on Wayland in Linux?

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How to do screen recording on Wayland in Linux? Many screen recorders do not work on the new Wayland. Using Green Recorder You may try Green Recorder which supports Wayland. Note: Green Recorder is no longer under development by the original author (Please check the project README for more details). It still works well for
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How to enlarge root partition and filesystem size of cloud Linux VM at runtime without rebooting Linux

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It is common that the root disk space is not enough when running a Virtual Machine in the cloud such as Amazon Web Service (AWS). The cloud storage usually provides tools or facilities to enlarge a virtual disk size. However, to make the Linux recognize and and use the enlarged disks without rebooting the OS,
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How to get date and time using date command from another timezone in Linux?

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date command on Linux gets the date and time in the system timezone. But how to get date and time using date command from another timezone in Linux? You can make date print the time of another timezone by setting the TZ environment variable. For example, export TZ=Hongkong; date Sat Dec 1 09:39:13 HKT 2018
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Installing Zlib Library in Ubuntu Linux

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On Ubuntu (18.04 and 20.04), installing zlib reported unable to locate package zlib: $ sudo apt install zlib Reading package lists… Done Building dependency tree Reading state information… Done E: Unable to locate package zlib How to install zlib in Ubuntu? Install zlib in Ubuntu from Ubuntu package repo In Ubuntu, the zlib package is
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Handling Sparse Files on Linux

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Sparse files are common in Linux/Unix and are also supported by Windows (e.g. NTFS) and macOSes (e.g. HFS+). Sparse files uses storage efficiently when the files have a lot of holes (contiguous ranges of bytes having the value of zero) by storing only metadata for the holes instead of using real disk blocks. They are
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How to Add a File Based Swap for Linux

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We may want to add some swap space for a Linux box while only find that all disk space is partitioned and mounted. Some partition has large available free space. For such cases, we may not want to change the partition allocation. The solution may be to add a file based swap for Linux as
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`readlink -m` equivalent function in Python to get canonical file name

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readlink -m can get canonical file name by resolving every symlinks in every component of the given path recursively. In Python, the os.readlink() function does not do so. Any equivalent function in Python to the readlink -m command line? Specifically, it does: canonicalize by following every symlink in every component of the given name recursively,
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How to operator[] access element in a const map in C++?

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How to operator[] access element in a const map in C++? For example, the compiler will report error on this piece of code: #include <iostream> #include <string> #include <map> std::int64_t count(const std::map<std::string, std::int64_t>& map) { return map[“one”] + map[“two”]; } int main () { std::map<std::string, std::int64_t> map = { {“one”, 1}, {“two”, 2} }; std::cout
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How to list start and end sectors of a partition by parted in Linux?

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How to list start and end of a partition by the sectors in parted on Linux? The default behavior seems be listing the start and end by bytes in parted. # parted /dev/sdc print Model: Innostor IS888 ext. HDD (scsi) Disk /dev/sdc: 2000GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End
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How to judge whether its STDERR is redirected to a file in a Bash script on Linux?

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Within a Bash script, how to judge whether its STDERR is redirected to a file in Bash on Linux? For example, ./script.sh /tmp/log 2>&1 Can script.sh detect that its STDERR is redirected? Knowing the destination file is better. To test whether a script’s STDERR (or STDOUT) is redirected to a file, check by [[ -f
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