SysTutorials Posts - Page 30 of 70

QA

How to merge git branches quickly and correctly
ByWeiwei Jia Mar 24, 2018Jan 7, 2020

Suppose I have following branches harryxiyou@common_vm ~/forest/sqle/sqle/scripts $ git branch * dev-harry master rc After I did some changes on dev-harry branch, I wanted to merge dev-harry into rc branch. 1, git checkout rc 2, git merge dev-harry References:http://stackoverflow.com/questions/24147169/merge-two-remote-branches-in-githttps://www.atlassian.com/git/tutorials/using-brancheshttp://git-scm.com/book/en/v2/Git-Branching-Basic-Branching-and-Merging I usually add –no-ff during git merge to force git to add a commit for the…

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QA

How can I recover deleted photos from samsung?
ByEric Ma Mar 24, 2018Mar 24, 2018

How can I recover deleted photos from samsung? You may try PhotoRec. A step by step tutorial can be found here. There are similar software. You can google them. Have you retrieved your lost photos from Galaxy? If not, you can follow the steps below to get some back. Hope it helps you somewhat. Stop…

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QA

When should the authors anonymize themselves in a paper submitted to a conference for review?
ByEric Ma Mar 24, 2018Mar 11, 2019

When should the authors anonymize themselves in a paper submitted to a conference for review? Several general concepts: Peer review is the evaluation of work by one or more people of similar competence to the producers of the work (peers). — Wikipedia Single-blind describes experiments where information that could introduce bias or otherwise skew the…

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QA

How to understand some key system consistency algorithoms
ByEric Ma Mar 24, 2018Mar 24, 2018

When we design a system, we may want our systems to be consistency, scalability and so on. Currently, there are some famous consistency algorithms. How to understand them easily. 1, Paxos and its extensions 2, Replicated State Machine mechanisms 3, Quorum Welcome to adding other famous consistency algorithms and its understanding ;-) Reading text books…

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QA

How to display chinese character in lxterminal
ByEric Ma Mar 24, 2018Mar 30, 2026

Do you know how to display chinese character in lxterminal? I tried to install lxterminal on my workstation and it seems display Chinese characters well: FYI, my Linux system is Fedora 41. The lxterminal version: $ rpm -q lxterminal lxterminal-0.1.11-10.fc21.x86_64 Not sure what’s the reason why it does not work for you. You may check…

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QA

How to measure a function’s execution time in OCaml?
ByEric Ma Mar 24, 2018Mar 24, 2018

How to measure the execution time of a function, say f: ‘a -> ‘b in OCaml? This small OCaml function is handy: let time f = let t = Unix.gettimeofday () in let res = f () in Printf.printf “Execution time: %f secondsn” (Unix.gettimeofday () -. t); res ;; The gettimeofday returns a float representing…

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QA

How to filter RSS feed items?
ByEric Ma Mar 24, 2018Feb 20, 2019

How to filter RSS items and leave only certain items that I want? Rules may be like: satisfies all or any rules { contains keyword; does not contain keyword } or etc. Two sServices that I find working well for me: Yahoo Piples: https://pipes.yahoo.com/pipes/</s> Pipes is a powerful composition tool to aggregate, manipulate, and mashup…

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QA

How to log connections hitting certain rules in iptables on Linux?
ByEric Ma Mar 24, 2018Mar 24, 2018

How to log connections hitting certain rules in iptables on Linux? Like the one that are dropped because of too frequently creating SSH connections. You can create a new chain named LOGNDROP that log the connections and drop them, then pass the connection to be redirected to the LOGNDROP chain. $tables -N LOGNDROP # Connections…

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QA

Basic iptables configuration for Linux
ByEric Ma Mar 24, 2018Mar 24, 2018

What is a good basic iptables config? Basic rules needed: Allow incoming TCP to 22 for SSH but blocks all others. Allow outgoing TCP/UDP connections. You may consider using the following rules as a start: for tables in iptables ip6tables ; do # Flush existing rules $tables -F # Default policy $tables -P INPUT DROP…

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How to list all running system service on Linux Mint 17.1?
ByEric Ma Mar 24, 2018Mar 24, 2018

How to list all running system service on Linux Mint 17.1? You can use initctl to list all services: initctl list

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QA

How to configure iptables on Linux Mint 17.1?
ByEric Ma Mar 24, 2018Mar 24, 2018

How to configure iptables and make the configuration persistent across system restarting on Linux Mint 17.1? You can use the ‘iptables-persistent’ tool. To install iptables-persistency pachage: sudo aptitude install iptables-persistent The you can manipulate the iptables by the ‘iptables’ command. To save the current iptables rules: sudo /etc/init.d/iptables-persistent store It will store the rules for…

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QA

How to use iptables to limit rates new SSH incoming connections from each IP on Linux?
ByEric Ma Mar 24, 2018Mar 24, 2018

How to use iptables to limit rates new SSH incoming connections from each IP on Linux? For example, at most 6 SSH connection attempts every 60 seconds. You may use these rules (skip the first one, if you have set the basic rules): for tables in iptables ip6tables ; do # Allow established inbound connections…

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How to upgrade packages installed by ELPA in Emacs?
ByEric Ma Mar 24, 2018Mar 24, 2018

ELPA manages packages for Emacs nicely. But, how to upgrade packages installed by ELPA in Emacs? Within Emacs, list all packages by M-x list-packages and it will automatically refresh the archive contents. Then, press U to mark all upgradable packages to be upgraded. Last, press x to perform the new updates. Emacs will then download…

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QA

How to make Alt key work in xterm?
ByEric Ma Mar 24, 2018Mar 24, 2018

Alt key seems not work in xterm. Alt is important for Emacs. How to make Alt key work in xterm? Put this in your ~/.Xresources file: XTerm*eightBitInput: false XTerm*eightBitOutput: true Remember to make it take effect after you change the ~/.Xresource without restarting the X server by xrdb -merge ~/.Xresources

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QA

Find Available Packages Versions using aptitude in Ubuntu
ByEric Ma Mar 24, 2018Sep 30, 2021

How to find the available packages’ versions with aptitude on Linux? With aptitude, you can use this command to show the available versions of a package: aptitude versions <package name> In the console GUI, aptitude also show the versions. You may also simulate installation of a package and see which version will be installed: aptitude…

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QA

How to install musl libc on Linux Mint 17?
ByEric Ma Mar 24, 2018Mar 30, 2026

How to install musl libc on Linux Mint 17/Ubuntu 24.04 LTS? You can install musl libc on Linux Mint 17 by sudo aptitude install musl musl-dev musl-tools One note: If you want to install a newer version of musl libc than the one from Ubuntu repo, you can use this ppa: https://launchpad.net/~bortis/ archive/ubuntu/musl by sudo…

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How to find the number of files in each directories on Linux?
ByEric Ma Mar 24, 2018Mar 24, 2018

How to find the number of files in each sub-directories of a directory on Linux? For example, . ├── a19 ├── a8 ├── d2 ├── ecfddd └── t1 The number of sub-directories can be quite large. How to find the number of files in each sub-directories here? You can use this piece of script to…

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QA

How to pull your git tree after creating it on remote server
ByEric Ma Mar 24, 2018Oct 20, 2020

Currently, I have created my branch dev-harry but I cannot pull it successfully as follows. harryxiyou@common_vm ~/forest/kvplus/kvplus $ git branch * dev-harry master rc harryxiyou@common_vm ~/forest/kvplus/kvplus $ git pull You asked me to pull without telling me which branch you want to merge with, and ‘branch.dev-harry.merge’ in your configuration file does not tell me, either….

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QA

How to exclude directories with certain names from rsync on Linux?
ByEric Ma Mar 24, 2018Mar 24, 2018

How to exclude directories with certain names like “cache” from rsync on Linux during backup? The “cache” directory may in many different paths, such as file1/cache/ or file2/cache/, and adding all “cache” directories to rsync command is not a doable way. You can use rsync with –exclude=cache/ like rsync -avxP –exclude=cache/ /path/to/src/directory/ /path/to/dst/dir/

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QA

How to play 3D movies in MPlayer?
ByEric Ma Mar 24, 2018Mar 24, 2018

How to play 3D movies in MPlayer on normal screen (2D)? You can play 3D movies on 2D screen by mplayer -vo gl_stereo=3 your.movie.file For the gl:stereo=3 option, check MPlayer man page: stereo=value Select a method for stereo display. You may have to use -aspect to fix the aspect value. Add 32 to swap left…

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