I configured the Linux password-less automatic ssh login as in this post . However, it still does not work for me. Any method to check it? The log in log /var/log/secure may give some clue on it. For example: Aug 20 23:16:10 doppler sshd[11143]: Authentication refused: bad ownership or modes for directory /home/useraaa tells us that…
How to convert a ps file to a pdf file that is available for publish (embedded fonts, etc)? Convert the file.ps ps file to file.pdf: $ ps2pdf -dPDFSETTINGS=/printer file.ps file.pdf</pre> Embedding Fonts in PDFs with pdflatex by Jeffrey P. Bigham: http://www.manticmoo.com/articles/jeff/programming/latex/embedding-fonts-with-pdflatex.php
How to install Dropbox on Linux ? Just follow Dropbox’s instruction here: https://www.dropbox.com/install?os=lnx A quick command for 64-bit Linux: $ cd ~ && wget -O – “https://www.dropbox.com/download?plat=lnx.x86_64” | tar xzf – Use the dropx CLI: http://www.dropboxwiki.com/Using_Dropbox_CLI Download dropbox.py: $ wget -O ~/bin/dropbox.py “https://www.dropbox.com/download?dl=packages/dropbox.py” Set the permissions: $ chmod +x ~/bin/dropbox.py Start Dropbox: $ dropbox.py start Status:…
Any good tools to synchronize home directories on Linux boxes? Many have several PC/laptops and consequently many home directories. There is home directory synchronizing problem. unison is a good tool to do this: http://www.cis.upenn.edu/~bcpierce/unison/download/releases/stable/unison-manual.html#rshmeth http://www.watzmann.net/blog/2009/02/my-homedirs-in-unison.html http://www.cis.upenn.edu/~bcpierce/papers/index.shtml#File%20Synchronization Useful script: $ unison -batch -ui text ./ /mnt/homebak/zma/ In text user interface, synchronizing two directories in batch mode…
If I have a disk with bad blocks, how to search bad blocks on it under Linux? You can use ‘badblocks’: https://www.systutorials.com/docs/linux/man/8-badblocks/ badblocks [ -svwnf ] [ -b block-size ] [ -c blocks_at_once ] [ -e max_bad_blocks ] [ -d read_delay_factor ] [ -i input_file ] [ -o output_file ] [ -p num_passes ] […
How to easily and quickly test the connection between two nodes on Linux? This should be specific to protocol and port. We can use nc (netcat) to test the connection between two servers. For example, to test whether TCP port 1048 can be used on the server (IP 10.0.3.48 as an example) side: On the server: $…
Any tutorials or tips on how to manage LVM? LVM provides a flexible and easy way to management storage disks on Linux. It also provides a set of tools for management. Here are some tutorials and references for managing LVM: LVM man pages: https://www.systutorials.com/docs/linux/man/8-lvm/#lbAL Manage Disk Volume in Linux: http://www.hongkedavid.com/blog/disk_volume.html LVM with Xen: https://www.systutorials.com/b/linux/tag/lvm/ Remove missing phyiscal volumes…
Evolution is a great personal information management tool that provides Email, address book and calendar tools. Evolution provides many enterprise friendly feature such as native support to Microsoft Exchange connectivity for Emails, address books and calendars. Evolution uses various ways including plain files and dconf configuration systems. This post will give an introduction to the…
We ever discussed fixing ports used by NFSv3 so that it can be easily exported to external networks. For NFSv4.1 or higher, things are much easier. The ports for mountd, statd, and lockd are not required in a pure NFSv4 environment. We have less ports to control or allow for connections. Only port 111 and…
The encoding of x86 and x86-64 instructions is well documented in Intel or AMD’s manuals. However, they are not quite easy for beginners to start with to learn encoding of the x86-64 instructions. In this post, I will give a list of useful manuals for understanding and studying the x86-64 instruction encoding, a brief introduction…
The metadata checkpointing in HDFS is done by the Secondary NameNode to merge the fsimage and the edits log files periodically and keep edits log size within a limit. For various reasons, the checkpointing by the Secondary NameNode may fail. For one example, HDFS SecondaraNameNode log shows errors in its log as follows. 2017-08-06 10:54:14,488…
Abstract Most popular task monitor systems (such as top, iotop, proc, etc) can only get tasks’ disk I/O information like tasks’ I/O utilization percentage every seconds due to kernel timer/tick frequency and high time cost of system interfaces. This article presents I/O Microscopy, a new way to get tasks’ disk I/O information with high accuracy….
Building Linux kernel may sound a complex and geek-only thing. However, as Linux kernel itself has much less depended tools/packages compared to other software packages, it is quite easy to compile, build and install a Linux kernel from the source code in an existing Linux OS. Building Linux kernel is needed if you need to…
In today’s time, data visualization has become a significant part of the success story of an organization. With the help of right techniques, visualizing data can reveal insights which the management staff can use in their decision-making in order to make sound data-driven decisions. Mapping software is among the robust data visualization tools that you…
Motivation Recently, I find it is hard to know the percentage of time that one process uses to wait for synchronous I/O (eg, read, etc). One way is to use the taskstats API provided by Linux Kernel [1]. However, for this way, the precision may be one problem. With this problem, I dig into Linux…
Making a career choice is difficult. And, if you have decided on becoming a programmer, the difficulty is just beginning. The most important thing is to first decide the language that you want to learn and this is often the most difficult decision. The good part is that you know you need to focus on…
In this tutorial, Microsoft Dynamics CRM India experts will teach you how to filter salutation based on Gender field in MS CRM. You can follow the step-by-step guide shared in this post to avail the results. Description- According to the requirement we need to filter salutation based on gender in contact entity. For this we…
Abstract In computer systems, resources have to be balanced so that the performance will be better based on the same hardware. In Linux Kernel system, we will see some migration kernel threads running as daemons to do this kind of jobs as follows. In this article, we will discuss how Linux Kernel balances its hardware/software…
Abstract Sometimes, we may want to migrate one process/thread to one specific CPU for some specific purpose. In the Unix/Linux systems, you may choose sched_setaffinity to finish this job. This article will help you to understand how sched_setaffinity (or other APIs like pthread_setaffinity_np in user-space) works internal Linux kernel. Details SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int,…
Since version 7, RHEL has only x86-64 versions. The same thing happens to CentOS 7. In CentOS 7/EPEL, there is only package for Wine x86-64. However, many Windows .exe files are 32-bit. Even there are 64-bit versions for some software, their installation file is 32-bit. And for some certain software such as Office 2007, 32-bit…