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2010-08-18 15:53:02

Vim tips

Almost 4PM...time for some vim tips. :-)

  • autocmd
    Vim's powerful autocmd feature can be used to automatically perform certain commands when a specific event occurs. The events that can be used as triggers range from creating a new file to resizing vim's window. A complete list of available triggers can be obtained by typing :help autocmd-events in vim. So, how's this useful?
    Let's say you write most of your Perl scripts in vim, why should you insert the shebang and some other stuff manually in a new file, when the editor can do this for you? The following two steps show you how it's done:
    1. Create a new file ~/.vim/skeletons/skeleton.pl containing a shebang for Perl as well as the recommended use strict/warnings statements:
      p=$(which perl); mkdir -p ~/.vim/skeletons; cat << EOF > ~/.vim/skeletons/skeleton.pl
      #!$p
      use strict;
      use warnings;
      EOF
      
    2. Put the following in your ~/.vimrc
      autocmd BufNewFile *.pl 0r ~/.vim/skeletons/skeleton.pl | :normal G
      
    Now, when you're creating a new *.pl-file it is automatically prepended with the contents of ~/.vim/skeletons/skeleton.pl and vim starts at the end of the file. Needless to say, that you can use multiple autocmd commands to support languages other than Perl.

  • Syntax check
    Everyone knows about vim's :make command, but did you know that it's possible to set the make program for each file type separately?
    autocmd FileType perl set makeprg=perl\ -c\ %\ $*
    
    By adding this to your ~/.vimrc, :make will no longer invoke make file but perl -c file instead, when you're editing a Perl script. As usual, Perl is just an example - i.e. Ruby programmers might use ruby -c or the like.

  • Y?
    There's some inconsistency between deleting and yanking in vim:
    dd deletes the current line, D deletes from the cursor to the end of the line.
    yy yanks the current line, but Y also yanks the current line...
    To yank all characters from the cursor position to the end of the line, you either need to type y$, or add a custom mapping for Y to your ~/.vimrc:
    map Y y$
    

  • Matchit
  • Typing % in normal mode finds the next item in the current line or under the cursor and jumps to its match. Items include c-style comments, parenthesis and some preprocessor statements. Unfortunately, there's no native support for HTML or Latex, but there's a handy little plugin, that adds support for these and many other languages: Matchit.
Enough for one day....

Posted by haui | Permanent link | File under: vim

2010-07-24 17:10:36

yaydl 1.5.2

yaydl 1.5.2 fixes the support for youtube....


Posted by haui | Permanent link | File under: projects

2010-07-20 22:08:42

Bandwidth monitors

There are many tools available, that allow you to monitor (among other things) the current downstream of your internet connection. Some of them, like dstat and bwm-ng are handy console applications, whereas others integrate nicely into your desktop. Two popular examples for this would be conky or gkrellm.
So, in general there's no real need for the following bash one-liner, unless you're just an ordinary user working on some poorly equipped linux box which doesn't offer any of the tools mentioned above. In that case, you'll be glad to have a dirty solution like the following available:

r=$(cat /sys/class/net/eth0/statistics/rx_bytes) ; while [ 1 ]; do n=$(cat /sys/class/net/eth0/statistics/rx_bytes); d=$(((n-r) / 1024 ));r=$n; echo "$d KB/s"; sleep 1;done

There is no need to mention,that eth0 must be replaced by your primary interface's name.

Posted by haui | Permanent link | File under: linux

2010-07-18 21:24:27

Remove Exif data

Sometimes it's advantageous to remove Exif metadata from image files, for example when posting images online. Fortunately, that's not a big deal since we're using linux:

mogrify -strip image.jpg
...or if you want to process more files:
mogrify -strip *.jpg

Posted by haui | Permanent link | File under: linux

2010-07-18 21:04:55

Important notice!!11


Posted by haui | Permanent link | File under: misc

2010-04-21 00:40:45

Linux, mplayer and the ZDF Mediathek

While the idea behind the ZDF Mediathek is not so bad at all, the actual implementation is a pain in the ass - especially the flash version of the website, which causes my Firefox to crash again and again...
So I tried the HTML version of the site, which has two major advantages:
1.) Firefox doesn't crash anymore and
2.) one can watch the videos with any external program like vlc or mplayer.

However, there's still a huge drawback: The videos are streamed via the Real-Time Streaming Protocol or the Microsoft Media Server Protocol, so basic operations like fast-forwarding, rewinding or pausing should be avoided. Additionally, as no (significant) buffering is performed, your internet connection will be in use for the whole runtime of a video, limiting other online activities.
Looking for an easy solution for this, I checked mplayer's manpage and found the -dumpstream option. The rest was some elementary bash scripting:

mplayer -dumpfile "$(date +%y_%m_%d_%H_%M.dump)" -dumpstream "$(curl -s "$(curl -s "$LINK" | egrep "<li>DSL\s*2000\s*<a href=.*asx" | sed -r 's#.*href="([^"]+)".*#\1#')" | egrep -o 'mms://[^"]+')"
This will save any(?) video from the Mediathek to a local file called *current_date*.dump. If you didn't figure it out by yourself, $LINK must be set to / replaced by the actual URL pointing to your video (you'll need the URL to the HTML version, or do some additional preprocessing first).

Before you ask: Of course I wrote an easy-to-use, ready-to-run script for this - it even does some limited error checking. It can be found here.


Update: Seems like this only works for just a few videos, so don't be too disappointed if it fails...


Posted by haui | Permanent link | File under: linux, scripts, perl

2010-04-10 21:40:47

yaydl 1.5.1

Version 1.5.1 comes with support for video.golem.de (ok....not as big as youtube, but who cares...)

BTW: If you want to be informed about new versions without reading my blog (shame on you!), you might want to subscribe to yaydl on freshmeat.


Posted by haui | Permanent link | File under: projects

2010-04-08 00:33:29

yaydl 1.5

I know, you've all been waiting for it, so without any further ado, here it is, yaydl 1.5!
It includes all new features from version 1.4a, as well as support for custom fmt codes. As usual, I also fixed some bugs - check out the changelog for details.


Posted by haui | Permanent link | File under: projects

2010-04-02 16:25:01

yaydl 1.4.5a

Still a alpha version, but youtube works again!


Posted by haui | Permanent link | File under: projects

2010-02-15 00:20:45

yaydl 1.4a

It's already been more than one month since I released yaydl 1.3.7, so it's time for a small status update. The attached preview of the upcoming release already includes two main new features: support for playlists and 1080p videos on Youtube. Please note that these improvements aren't fully stable yet and might include some bugs - so if you're a fan of rock-stable software, keep your hands off this alpha ;-)


Posted by haui | Permanent link | File under: projects

2010-02-02 21:26:50

Lyrics fetcher for moc

As the newest alpha version of moc comes with the ability to display song lyrics, I thought it might be a nice feature to fetch these lyrics automatically. So I just cobbled together a few lines perl code, that actually work pretty well. Nevertheless it's just a quick hack with a lot of bugs, so don't expect too much. :-)


Posted by haui | Permanent link | File under: linux

2010-02-01 20:05:39

HowTo: Convert Windows-style line endings to Unix-style (and vice versa)

Though there are some tools (e.g. dos2unix) available to convert between DOS/Windows (\r\n) and Unix (\n) line endings, you'd sometimes like to solve this rather simple task with tools available on any linux box you connect to. So, here are some examples - just pick the one that fits you best:

Windows to Unix:

#Shell
perl -pe '$_=~s#\r\n#\n#' < windows.txt [> linux.txt]
sed -r 's/\r$//' windows.txt [> linux.txt]

#Vim
:%s/\r$//
:set ff=unix

Unix to Windows (do you really want this?)
#Shell
perl -pe '$_=~s#\n#\r\n#' < linux.txt [> windows.txt]
sed -r 's/$/\r/' linux.txt [> windows.txt]

#Vim
:set ff=dos
Don't forget to save your file, when you're using vim.

Posted by haui | Permanent link | File under: linux

2010-01-06 21:19:48

yaydl 1.3.7

A new year - a new version of yaydl. Apart from the usual bugfixes, one new feature found its way into this release: From now on, yaydl has direct support for inputfiles, which renders the workaround via shell I/O redirection obsolete. As always, the commandline option for this and all other functions can be found in the readme file. ;-)


Posted by haui | Permanent link | File under: projects

2009-11-04 20:58:30

yaydl 1.3.6

After so many people asked me to waste some more blog entries on yaydl, I eventually found some spare time to comply with their request. ;-)
However, if you were expecting some fancy new features, don't get too overexcited: v1.3.6 is just another bugfix release. Yet, I'm confident I'll extend yaydl's functionality till autumn 2010. :D


Posted by haui | Permanent link | File under: projects

2009-08-03 21:08:00

yaydl 1.3.5

One very small bugfix, barely worth mentioning....


Posted by haui | Permanent link | File under: projects