Wednesday, October 16, 2013

long PATH, LD_LIBRARY_PATH, … – what kind of performance impact do they have?

A long PATH… makes the OS …
  1. "… access the disk quite often, hence there is a lot of disk I/O" – do you agree?
  2. "… compute a lot of …, hence a high CPU load" – do you agree?
  3. …
I got involved in a rather "controversial" discussion on that. I voted for (1). What are you voting for?

I posted this issue at http://www.unix.com/shell-programming-scripting/238465-long-path-ld_library_path-libpath-what-kind-performance-impact-do-they-have.html as well.

"Lexical File Names in Plan 9" or "Getting Dot-Dot Right" (an article on symlinks in Unix)

http://www.cs.bell-labs.com/sys/doc/lexnames.html

An article on symlinks in Unix.
ABSTRACT
Symbolic links make the Unix file system non-hierarchical, resulting in multiple valid path names for a given file. This ambiguity is a source of confusion, especially since some shells work overtime to present a consistent view from programs such as pwd, while other programs and the kernel itself do nothing about the problem.
Plan 9 has no symbolic links but it does have other mechanisms that produce the same difficulty. Moreover, Plan 9 is founded on the ability to control a program’s environment by manipulating its name space. Ambiguous names muddle the result of operations such as copying a name space across the network.
To address these problems, the Plan 9 kernel has been modified to maintain an accurate path name for every active file (open file, working directory, mount table entry) in the system. The definition of ‘accurate’ is that the path name for a file is guaranteed to be the rooted, absolute name the program used to acquire it. These names are maintained by an efficient method that combines lexical processing—such as evaluating .. by just removing the last path name element of a directory—with local operations within the file system to maintain a consistently, easily understood view of the name system. Ambiguous situations are resolved by examining the lexically maintained names themselves.
A new kernel call, fd2path, returns the file name associated with an open file, permitting the use of reliable names to improve system services ranging from pwd to debugging. Although this work was done in Plan 9, Unix systems could also benefit from the addition of a method to recover the accurate name of an open file or the current directory.

O'Reilly Media book: X Power Tools

http://shop.oreilly.com/product/9780596101954.do

O'Reilly Media book: Linux Server Hacks, Volume Two

http://shop.oreilly.com/product/9780596100827.do

O'Reilly Media book: Linux Annoyances for Geeks

http://shop.oreilly.com/product/9780596008017.do

Sunday, October 13, 2013

FAQ: what USB speakers and DACs do Synology products support?

Friday, October 11, 2013

DVB-C (and DVB-T2/-T) for my Synolgy NAS "diskstations"

It needs the following software:

    These two mentioned diskstations are compatible with these two DVB-C USB connectable devices:

    This DVB-T2 /-T/-C USB connectable device would be my favourite, if it were supported by dvblogic for the NAS-s mentioned above and also for the Raspberry Pi:

    Q: "Catmatism"? A: just opposite of Dogmatism -"Accepting the changes without being dogmatic"

    Urban Dictionary: Catmatism

    A person who adopts a positive and revolutionary changes accordingly without being stubborn or stereotyped, is supposed to follow Catmatism. (sp?)

    Wednesday, October 9, 2013

    displaying files (on a UNIX command line), each file together with its names

    displays each file with its name before its content:
    $ head -999 file-a file-b file-c

    displays each file with its name before each line of its content:
    $ pipegrep '' cat file-a file-b file-c

    Search the web for pipegrep, if you are interested in it! It is written in one word.

    how to easily display a base64 encoded file

    I wondered, how I could achieve that on various Unix platforms, and I ran the following command on my Linux box:

    $ man -k base64
    base64 (1)           - base64 encode/decode data and print to standard output
    MIME::Base64 (3pm)   - Encoding and decoding of base64 strings

    Right the utility base64 (beloning to GNU coreutils) would do it, if it were broadly available; on AIX you can't expect GNU coreutils to be installed.
    The MIME::Base64 man page shows a nice perl one-liner making use of a perl module, which is rather likely to be installed:

    $ perl -MMIME::Base64 -ne 'print decode_base64($_)'

    TidBITS Publishing e-book (only): Take Control of 1Password

    Take Control of 1Password:
    Speed through Web logins with 1Password 4!
    Remembering and entering Web passwords is both difficult and insecure, but it doesn't have to be that way, thanks to 1Password, the popular password manager from AgileBits. In this ebook, Joe Kissell brings years of real-world 1Password experience into play--plus many hours with the 1Password 4 for Mac beta--to explain not only how to create, edit, and enter Web login data easily, but also how to autofill contact and credit card information when shopping online, audit your passwords and generate better ones, and share your passwords with key people and among multiple devices. Joe focuses on 1Password 4 for the Mac, but he also provides details and directions for the iOS, Windows, and Android versions of 1Password.
    You'll find expert advice on these topics:
    Meet 1Password: Set your master passcode and make first-run configuration decisions. Explore usage strategies for 1Password on your Mac, PC, iOS device, or Android handheld, and understand the different components of the software on the different platforms. Get lots of ideas for how to share your vault (or vaults!) among your devices and with other people.
    Master logins: In 1Password, a typical login contains a set of credentials used to sign in to a Web site. Find out how to create logins, sort them, search them, tag them, delete them, and more. You'll especially find help with editing logins. For example, if you change a password from dragon7 to eatsevendragonsforlunchatyahoo, you'll want to incorporate that into its login. Or, use 1Password's password generator to come up with complex passwords, like dGx7Crve3WucELF#s.
    Understand password security: Get guidance on what makes for a good password, and read Joe's important Password Dos and Don'ts. An advanced topic later in the ebook covers how to perform a security audit in order to improve poor passwords quickly. (For Joe's full advice on passwords, read Take Control of Your Passwords.)
    Go beyond Web logins: For a lot of people, a primary point of 1Password is to speed the process of signing in to Web sites. But 1Password can do much more. Learn about storing and autofilling contact information (for more than one identity, even), and your credit card number and security code. You'll also find advice on storing passwords for password-protected files and encrypted disk images, plus ideas for keeping track of confidential files, private diary entries, scans of important cards or documents, and more.
    You'll also discover the answers to key questions, including:
    • What are the main changes between 1Password 3 and 1Password 4?
    • In addition to 1Password, should I use my Web browser's password, contact, or credit card autofill feature? What about Apple's iCloud Keychain?
    • What is the fastest way to get 1Password to sign me in to a Web site?
    • My login item used to sign me in, but it stopped working. What should I do?
    • I made a long, random password for my bank account, but it wasn't saved in the login item! Where can I find it?
    • How can I use one username and password with multiple Web sites, like one Apple ID for both iCloud and the online Apple Store?
    • What if I need to access my 1Password data from another person's computer?
    • How can I speed up Web logins and filling in shopping cart info with 1Password in iOS or Android?
    • Is it true that I can initiate 1Password login items from keyboard launcher utilities like LaunchBar, Alfred, and Quicksilver? (Hint: the answer is yes!)

    O'Reilly Media book: OS X Mavericks: The Missing Manual

    http://shop.oreilly.com/product/0636920029069.do:
    With Mavericks, Apple has unleashed the most innovative version of OS X yet—and once again, David Pogue brings his humor and expertise to the #1 bestselling Mac book. Mac OS X 10.9 brings more innovations from the iPad and adds a variety of new features throughout the operating system.

    O'Reilly Media book: Windows 8.1: Out of the Box

    http://shop.oreilly.com/product/0636920032533.do:
    Get a real feel for Windows 8.1 with a wealth of tips in this step-by-step guide. After using Windows 7 or XP, learning Microsoft’s latest operating system takes some adjustment. Never fear. Windows expert Mike Halsey starts with the basics and then takes you through the trickier parts of Microsoft’s latest operating system.

    Wednesday, September 25, 2013

    O'Reilly Media book: Unix Power Tools, 3rd Edition (2002)


    a couple of nice utilities from their sample code:
    • rcsgrep, rcsegrep, rcsfgrep - check out files and grep/egrep/fgrep them – is there somthing similar for subversion etc.?
    • …
    Update 2013-10-23:
    Derived cvsrevs from rcsrevs, and cvsgrep from rcsgrep. This is really nice!! Imagine this:
    $ cvsgrep -a SEARCHME files…

    do you remember "pipegrep" from a rather old Camel Book?

    [Chapter 27] 27.13 More grep-like Programs Written in Perl (an outdated but still useful "Unix Power Tools" edition somewhere on a web-server discusses it)

    The pipegrep program greps the output of a series of commands. The difficulty with doing this using the normal grep program is that you lose track of which file was being processed. This program prints out the command it was executing at the time, including the filename. The command, which is a single argument, will be executed once for each file in the list. If you give the string {} anywhere in the command, the filename will be substituted at that point. Otherwise the filename will be added on to the end of the command. This program has one option, -l, which causes it to list the files containing the pattern.

    Follow the above link for a nice example!

    I remembered the pipegrep utility today, because I came across a task …

    Update 2013-10-17:

    O'Reilly Media book: Oracle PL/SQL Programming

    Oracle PL/SQL Programming:
    Considered throughout the Oracle technology community to be the best Oracle PL/SQL programming book available, this guide is the definitive reference on Oracle’s powerful procedural language. Like its predecessors, this sixth edition covers language fundamentals, advanced coding techniques, and best practices for using PL/SQL. Thoroughly updated for Oracle Database 12c.

    GNU Coding Standards: Option Table (command line options)

    GNU Coding Standards: Option Table

    Wednesday, September 18, 2013

    how to let GNU Emacs "Untabify Upon Save"?

    EmacsWiki: Untabify Upon Save

    There are colleagues, that don't want to see tabs in scripts sources, that I edited.

    Apparently there isn't a nice switch saying, that there shouldn't be tabs in a certain file.

    Tuesday, September 17, 2013

    Greg Kroah-Hartman: booting a self-signed Linux kernel

    booting a self-signed Linux kernel - Linux Kernel Monkey Log

    Procedures for how to boot a self-signed Linux kernel on a platform so that you do not have to rely on any external signing authority.

    Sunday, September 15, 2013

    my new UPS: APC BE700G-GR


    • Now my Synology DS213+ (NAS) gets its power from the UPS, and the UPS also controls USB-wise, when the NAS goes to "Safe Mode". For the USB-connected NAS, this is "local UPS support". This Synology device is now the "Synology UPS server", that controls, the remaining Synology DiskStations powered by the UPS.
    • My Synology DS112+ (NAS) uses the DS213+ as "Synology UPS server".
    It feels well, to have your NAS-s powered by your UPS.

    an "Erich Fromm" page on Facebook in English

    www.facebook.com/pages/Erich-Fromm/25431672903

    UPS on the Synology wiki

    User Reported Compatible Uninterruptible Power Supplies - SynologyWiki

    Tuesday, September 10, 2013

    my latest GNU Emacs on OS X: Emacs Daily Build 2013-09-11

    Emacs Daily Build 2013-09-11 »:
    Universal Binary built on Mac OS X 10.6.8, 45.89 MB.
    See the differences from the last build.

    yet another Perl power tool: ack - grep-like text finder

    ack - grep-like text finder - metacpan.org - Perl programming language

    added "Perl Power Tools" to the PPT "disambiguation page" on the English wikipedia

    en.wikipedia.org/wiki/PPT

    I am curious, how long this entry will survive there. It's actually not referring to an existing article on the Perl Power Tools. It's just meant to tell "the reader", hey, there are these nice Perl Power Tools out there, and they also get abbreviated as PPT.

    Well, yes, I could create a wikipedia stub page, but it would only have these 2 links:

    And maybe some short text with like 30 words from the first of these 2 links.

    But for how long would this stub article survive on wikipedia?

    the Unix date command: yesterday, tomorrow, nanoseconds

    GNU's date lets you specify yesterday, tomorrow, Sunday, … to be displayed following the format specification you supply. And (if available) you can also get nanoseconds displayed. Please do not complain, that precisions between nanoseconds and seconds are missing!

    Maybe on your UNIX flavor computer GNU date is installed as gnudate or gdate (just like: gnutar, gtar, …).

    Monday, September 9, 2013

    No Starch Press: Perl One-Liners

    http://shop.oreilly.com/product/9781593275204.do:
    Perl One-Liners showcases 130 short and compelling lines of code that do all sorts of handy, geeky things.

    TidBITS Publishing e-book (only): Take Control of Your Online Privacy

    http://shop.oreilly.com/product/9781615424252.do
    Learn what's private online (not much)--and what to do about it!
    Do you have anything to hide? Whether or not you think you do, your online activities are certainly tracked -- and not just by well-meaning sites who want to keep you logged in or by marketing firms who want to show you targeted ads for products that you likely want to buy.
    In the full book, Joe helps you gain perspective on what is reasonable to expect about online privacy and develop a sensible online privacy strategy, customized for your needs. He then explains how to enhance the privacy of your Internet connection, Web browsing, email messages, online chatting, social media interactions, and file sharing. To bring home the most important privacy no-nos, Joe also encourages you to take The Pledge (OK, it's tongue-in-cheek, though it would have saved numerous politicians from ridicule and career-ending gaffes). Plus, parents will find important riinders about how your online actions can affect your children, far into the future.
    Teach This Book! Once you're satisfied with your own online privacy strategy, you may want to help friends or colleagues improve theirs. To that end, Take Control of Your Online Privacy includes links to a downloadable one-page PDF handout and to a PDF-based slide deck that you can show on any computer or mobile device screen.
    Whether you have a Mac or PC, iOS or Android device, set-top box, cell phone, or some other network-enabled gadget, Take Control of Your Online Privacy has the advice that ordinary people need to handle common privacy needs (secret agents should really look elsewhere). You'll receive savvy advice about:
    Why worry? Learn about who wants your private data, and, more important, why they want it. Even if you don't believe you have anything to hide, you almost certainly do, in the right context. Would you give just anyone your financial records or medical history? Didn't think so.
    Set your privacy meter: Develop your own set of personal privacy rules -- everyone has different privacy buttons, and it's important to figure out which are important to you.
    Manage your Internet connection: Understand privacy risks, prevent snoops, and take key precautions to keep your data from leaking out.
    Browse and search the Web: Learn what information is revealed about you when you use the Web. Avoid bogus Web sites, connect securely where possible, control your cookies and history, block ads, browse and search anonymously, and find out who is tracking you. Also, learn how to protect your passwords and credit card data.
    Send and receive email: Find out how your email could be intercepted, consider when you want email to be extra private (such as when communicating with a doctor or lawyer), find out why Joe doesn't recommend email encryption as a solution to ordinary privacy needs (but find pointers for how to get started if you want to try it -- or just encrypt an attachment, which is easier), get tips for sending email anonymously, and read ideas for alternatives to email.
    Talk and chat online: Consider to what extent any phone call, text message, or online chat is private and find tips for enhancing your privacy when using these channels.
    Watch your social media sharing: Social media is by definition social, so there's a limit to how private it can be. Understand the risks and benefits of sharing personal information online, tweak your settings, and consider common-sense precautions.
    Share files: What if you want to share (or collaborate on) a contract, form, or other document that contains confidential or personal information? Find out about the best ways to share files via file server, email attachment, cloud-based file sharing service, peer-to-peer file sharing, or private cloud.
    Help your children: As a parent, you know a lot about your children and you have access to lots of photos of thi. But that doesn't mean you should share everything without a thought to your children's privacy needs, either now or in the future, since data never disappears from the Internet. Find a few key tips to keep in mind before you tell all.
    If I don't live in the United States, does this book pertain to me?
    Many of the examples in this book are taken from the United States. Although laws and policies vary from country to country, nearly everything in this book is applicable in some fashion to anyone in the world.
    I am a journalist and need to protect my sources. Plus, I think a few governments are tracking my movements. Will this ebook help me to ensure my privacy?
    This book could be a good start if you are unfamiliar with these matters, but it does not have the depth of technical detail that you require. The intention of this ebook is to help ordinary people address ordinary privacy concerns, within the scope of a short book.