Linux Kernel: PM / clk: Fix clock error check in __pm_clk_add()

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This change "PM / clk: Fix clock error check in __pm_clk_add()" (commit 3fc3a0b) in Linux kernel is authored by Geert Uytterhoeven <geert+renesas [at] glider.be> on Fri May 8 10:47:43 2015 +0200. Description of "PM / clk: Fix clock error check in __pm_clk_add()" The change "PM / clk: Fix clock error check in __pm_clk_add()" introduces changes
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Linux Kernel: netpoll: fix netconsole IPv6 setup

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This change "netpoll: fix netconsole IPv6 setup" (commit 00fe11b) in Linux kernel is authored by Sabrina Dubroca <sd [at] queasysnail.net> on Thu Feb 6 18:34:12 2014 +0100. Description of "netpoll: fix netconsole IPv6 setup" The change "netpoll: fix netconsole IPv6 setup" introduces changes as follows. netpoll: fix netconsole IPv6 setup Currently, to make netconsole start
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Linux Kernel: cifs: release auth_key.response for reconnect

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This change "cifs: release auth_key.response for reconnect." (commit f5c4ba8) in Linux kernel is authored by Shu Wang <shuwang [at] redhat.com> on Fri Sep 8 18:48:33 2017 +0800. Description of "cifs: release auth_key.response for reconnect." The change "cifs: release auth_key.response for reconnect." introduces changes as follows. cifs: release auth_key.response for reconnect. There is a race that
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Linux Kernel 4.19.70 Release

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This post summarizes new features, bugfixes and changes in Linux kernel release 4.19.70. Linux 4.19.70 Release contains 95 changes, patches or new features. In total, there are 101,521 lines of Linux source code changed/added in Linux 4.19.70 release compared to Linux 4.19 release. To view the source code of Linux 4.19.70 kernel release online, please
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Linux Kernel: ALSA: hda/realtek – Fix Headphone Mic doesn’t recording for ALC256

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This change "ALSA: hda/realtek – Fix Headphone Mic doesn’t recording for ALC256" (commit d32b666) in Linux kernel is authored by Kailang Yang <kailang [at] realtek.com> on Thu Apr 23 15:10:53 2015 +0800. Description of "ALSA: hda/realtek – Fix Headphone Mic doesn’t recording for ALC256" The change "ALSA: hda/realtek – Fix Headphone Mic doesn’t recording for
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Linux Kernel: fs: handle SEEK_HOLE/SEEK_DATA properly in all fs’s that define their own llseek

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This change "fs: handle SEEK_HOLE/SEEK_DATA properly in all fs’s that define their own llseek" (commit 06222e4) in Linux kernel is authored by Josef Bacik <josef [at] redhat.com> on Mon Jul 18 13:21:38 2011 -0400. Description of "fs: handle SEEK_HOLE/SEEK_DATA properly in all fs’s that define their own llseek" The change "fs: handle SEEK_HOLE/SEEK_DATA properly in
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Linux User Group Management and Operations

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Linux allows more than one users to log into the system to run processes/programs at the same time. In order to make this multi-user system work properly, Linux provides ways to isolate and protect users from each other and manage the permissions efficiently. One of the mechanism is user groups. Linux users may be grouped
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Compress PNG Images on Linux

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PNG images already use DEFLATE data compression algorithm involving a combination of LZ77 and Huffman coding. But the PNG images can be further compressed by removing non-important metadata or using lossy compression to save storage space and/or data transfer bandwidth. In this post, we introduce 2 compression ways with tools available on Linux. Lossless compression
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Make Grub2 Boot Older Kernel Version in Ubuntu 20.04

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In a Linux system, we may have multiple kernels installed. Usually, it is the latest kernel configured to be the default one the system boot loader will use during automatic boot if there is no manual kernel choosing. In many cases, such as there is no driver ready yet for some devices in newer kernels,
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Add Inline Comments for Multi-line Command in Bash Script

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In Bash script, it is common that multiple small commands run together connected by pipes (|) and the whole command is quite long. For clarity, we may write the command in multiple lines. How to add comments for these long multi-line commands? In Bash, the content after # in a line is the comment. Using
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Grep 2 Lines using `grep` Command in Linux

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grep is excellent to match patterns from STDOUT/text files in command line or scripts. It’s handy. Sometimes, our problem is more complex than finding a keyword from a file. On a first thought, it may sound impossible using grep for such complex problems. But grep can be quite powerful than we thought. Today, let’s check
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How to Install Go 1.13.x on Ubuntu 18.04

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In Ubuntu 18.04 LTS, the default Go lang version is 1.10. For compatibility reason, the Ubuntu LTS will usually keep the major release version numbers for packages. However, many applications, such as Hyperledger Fabric 2.0, require a newer version of Go. In this post, let’s take a look at how to install a system level
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GCC May “Save” You Some Recursive Functions Calls: an Analysis of a Function Call Stack Length Example

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We know compilers like gcc can do lots smart optimization to make the program run faster. Regarding functions call optimization, gcc can do tail-call elimination to save the cost of allocating a new stack frame, and tail recursion elimination to turn a recursive function to non-recursive iterative one. gcc can even transform some recursive functions
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Bash Learning Materials

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Bash (GNU Bourne-Again SHell) the default shell for many Linux distributions. It is very common for scripting languages in Linux. Bash is easy and straightforward for writing small tools. However, as most tools, it has its grammars that could easily cause bugs if they are not used correctly. Here I summarize a list of good
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How to Install Wine 32-bit on CentOS 8

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Since version 7, RHEL and CentOS only have 64 bit versions. For some reasons, it’s better to run many Windows applications under 32 bit wine. Like How to Install Wine 32-bit on CentOS 7, this post introduce how to install 32-bit Wine on CentOS 8. Most of the mechanisms are similar yet there are differences.
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How to synchronize OneDrive and OneDrive for Business files in Linux using Insync

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OneDrive is one of the good cloud storage services available and there is a business version called OneDrive for Business. Microsoft’s Office 365 plan is widely used including Exchange Email service and OneDrive for Business. However, there is no official client released yet for Linux users. Insync is a third party cloud storage syncing software
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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 synchronize Google Drive and Google Docs files in Ubuntu/Debian/Mint Linux using Insync

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Google Drive is a nice cloud storage service. It provides a suite of nice online document spreadsheet and slide editors Google Docs, Google Sheets and Google Slides. The collaborative editing and full history tracking features of Google Docs are excellent. Google Drive gives 16GB free storage which is pretty much larger compared to other free
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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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