References in a sub-select

- 19 Jan 2017
  
  References in a sub-select
  
  Written by Alex Wood
  Have you ever had a sub-select where you really needed to reference a value in the outer query? I know I have! The naive way would be to run the outer query and then loop over the results running the inner query on each one. Luckily, there’s a better way. The Correlated subquery. Check it out! The example given is
  
  SELECT employee_number, name FROM employees AS Bob WHERE salary > ( SELECT AVG(salary) FROM employees WHERE department = Bob.department);
  
  See how the sub-select references the outer query? It’s SQL magic.
  0 Comments
- 23 Oct 2015
  
  SSL Renewal And You
  
  Written by Tim Bielawa
  
  This post is about renewing SSL certificates. There’s not a lot of information I want to communicate here, so I’m going to keep it short.
  
  Yesterday the SSL certificate for https://blog.lnx.cx expired. I don’t know much about SSL, other than I find it more confusing/complicated than most things. I knew that I needed to renew the SSL certificate for the blog, but I did not know what that exactly meant. When I called my cert provider on the phone to renew, they told me that the renewal process begins with submitting a new Certificate Signing Request, or CSR in crypto parlance. We ended the call shortly thereafter and I set off to get started.
  
  I still had questions though. If I’m “renewing” my SSL certificate, does that mean my existing certificate is involved in some way? When I began reviewing the CSR generation procedure I saw no references to existing certificates. I did a bit of Internet research to try and figure this out.
  
  Eventually I found out that the idea of “renewing” a certificate is a bit of a misnomer. That is, nothing you have carries over with you. The process of “renewing” a certificate is actually the exact same process as getting an initial certificate. I’ll say that again for clarity:
  
  Renewing an SSL certificate is the exact same thing as getting your first SSL certificate.
  
  I hope this helps out other folks who are as confused as I was about the renewal process.
  
  0 Comments
- 15 May 2015
  
  Getting consistent fingerprints from git-archive
  
  Written by Alex Wood
  
  The “git archive” man page states:
  
  git archive behaves differently when given a tree ID versus when given a commit ID or tag ID. In the first case the current time is used as the modification time of each file in the archive.
  
  By using the current time in this case, git-archive is dooming all of our tarballs to have constantly changing SHA256 hashes. A lot of build systems, including Fedora’s Koji, rely on source tarballs maintaining a consistent fingerprint. What is a person to do?
  
  Fix it of course! Below is a Python 2 program I wrote that addresses the issue. The code is well-commented (I hope) so you should be able to follow along. You give it the Unix timestamp you want the files to have, the git ref you want baked into the tar header, and the initial tarball. The result is printed to stdout so just redirect that to wherever you please (or pipe it into gzip). It also has some code in there to deal with tarballs created by the maven-assembly plugin, but it doesn’t surface that on the primitive CLI. I’m leaving that as an exercise for the reader I guess.
  
  0 Comments
- 16 Mar 2015
  
  Open URL Bug with XDG on XFCE4
  
  Written by Alex Wood
  Recently I noticed that in my IRC client, when I right-click a URL and select “Open Link In Browser”, the system would open a new browser window (or tab if appropriate) but not pointed to the link I wanted to visit. It would just open the home page.
  
  What gives? Well, I happen to know from experience that in Linux most programs that need to use a “default” type service of which there are many implementations (such as a web-browser) use the xdg-open command. XDG associates different mime-types to default applications. Step one then is to figure out what’s going on with XDG.
```
% xdg-mime query default text/html
firefox.desktop firefox.desktop
```
  Here I’m asking XDG what applications are associated with the text/html mime-type. Seeing two firefox.desktop files was a bit of a surprise. Let’s find out more!
```
% locate firefox.desktop
/usr/share/applications/firefox.desktop
/usr/share/xfce4/helpers/firefox.desktop
```
  So I open up those two files and the first file looks normal and that file actually belongs to the Firefox package according to rpm -qf. In the second file, I see
```
X-XFCE-Commands=%B -remote "openURL(about:blank,new-window)";%B;
X-XFCE-CommandsWithParameter=%B -remote "openURL(%s,new-window)";%B "%s";
```
  That looks strange to me. If I want to open a URL from the command line, I don’t use openURL. Let’s see what happens if I replace that with
```
X-XFCE-Commands=%B;
X-XFCE-CommandsWithParameter=%B "%s";
```
  Aha! It works! But why? Well, after a little searching I came across Mozilla Bug 1080319. Looks like the openURL was a legacy thing and got removed in Firefox 36. And a quick rpm -q firefox confirms that I’m running that version. Firefox 36.0.1 add support for openURL back in, but my hack will serve until that version hits Fedora.
  0 Comments
- 14 Aug 2012
  
  Weechat
  
  Written by Tim Bielawa
  Plugins (“Scripts”)
  
  Show the channels you have joined
  - From: http://www.weechat.org/scripts/source/stable/buffers.pl.html/
  - No setup required to get going.
  - Drop into ~/.weechat/perl/autoload
  Direct message notifications
  - http://www.weechat.org/scripts/source/stable/notify.py.html/
  - No setup required to get going.
  - Drop into ~/.weechat/python/autoload
  Needs some tweaks on Gnome 3 though for better functionality
  - http://pastebin.com/7iuu9Bn9
  Explanation for having this:
  
  By default, in GNOME3 every notification you recieve from weechat will stack up in your notification panel until acknowledged. This is not my idea of ideal. In libnotify, setting notifications to transient (see patch) means that they will not hang around on your notification panel forever — waiting for you to acknowledge them — one-by-one, before they disappear
  
  Plugin for opening links in your browser
  - From: http://www.weechat.org/scripts/source/stable/urlgrab.py.html/
  - Useful with a /open alias, see the aliases section below.
  - Drop into ~/.weechat/python/autoload
  Why not just click the links normally? Presumably, you’re running weechat in a terminal, this will cause long links to hard-wrap around the screen. When the links are hard-wrapped like this it causes the clickable portion of the URL to become truncated (you won’t be able to click the full url).
  
  With this plugin you can use a simple command (within weechat) to launch links for you. The plugin watches your channels for text that looks like links and makes a note of them.
  
  This has one obvious limitation: it doesn’t work well if you’re running weechat on a remote host, i.e., you have to ssh to the host you run weechat on. (But there are ways around that).
  
  Built-In Keybindings
  
  Go to the buffer I was last pinged in
  - Alt + a
  Go to buffer #
  - Alt + #
  - Usage:
    
    Alt + 5
  - The current window will now display buffer number 5
  See the next tip if you need to show a buffer whose number is two or more digits.
  
  Go to buffer ##
  - Alt + j ##
  - Usage:
    
    Alt + j 10
  The current window will now display buffer number 10
  
  Moving your cursor focus between split windows
  - Previous Window: F7
  - Next Window: F8
  Clear all activity/notification colors from your buffer list
  - Alt + h
  Go up/down channels (“buffers”)
  - Ctrl + N
  - Ctrl + P
  Helpful Custom Key Bindings
  
  Scrolling the user list
  - Scroll down is F12 by default
  - Scroll up is F11 by default
  This conflicts with the common F11 = full screen idiom. Instead, lets leave F12 as scroll down, but make Shift + F12 scroll up.
  - /key bind meta2-24;2~ /bar scroll nicklist * y-100%
  Enter it exactly as shown: with the tilde (~) and semicolon (;).
  
  User Interface Tweaks
  
  More colors for users nicks
  
  WeeChat >= 0.3.5, terminal with 256 colors
  - Run the command in this link: http://lnx.cx/~tbielawa/blog/weechat_nick_colors.txt
  - From: http://dev.weechat.org/post/2011/08/28/Beautify-your-WeeChat
  Don’t show every join/part/quit
  - /set irc.look.smart_filter on
  - /filter add irc_smart * irc_smart_filter *
  - /set irc.look.smart_filter_delay 5
  - From: http://dev.weechat.org/post/2008/10/25/Smart-IRC-join-part-quit-message-filter
  If you want to see who has joined/left recently, press ALT + = (alt and the equals key). Pressing it again rehides the notices.
  
  Fix the buffer titles
  
  You may have a problem where your buffer titles (channel topics) only color the bar to the end of their text. This is a configuration issue and the fix is documented on the weechat FAQ.
  
  Useful Basic Aliases (“slash command” shortcuts)
  
  Set a handle on multiple servers
  
  At work I am logged into three IRC networks all day long: devel, corp, and freenode, I use this to set a status (tbielawa|brb, or tbielawa|wfh, …) on all three at once:
  - /alias appendnick /allserv nick tbielawa|$*
  - Usage:
    
    /appendnick wfh
  Nick on all networks is now: tbielawa|wfh.
  
  Close the current buffer (channel window)
  - /alias cb /buffer close
  - Usage:
    
    /cb
  Reconnect to multiple networks
  
  If I have been disconnected (dropped off the VPN, or switched locations) and I need to reconnect to all my IRC networks I use this:
  - /alias rejoin /reconnect -all
  - Usage:
    
    /rejoin
  Open the last URL posted
  
  If you’re using the urlgrab.py plugin (above), this will open the last URL it found in your current channel:
  - /alias open /url 1
  - Usage:
    
    /open
  The last link sent in your channel will be launched in your browser.
  
  Split into three windows
  
  Split weechat into three horizontally stacked windows:
  - /alias split3 /window splith 33; /window +1; /window splith
  - Usage:
    
    /split3
  I don’t normally run this by hand, it’s actually a part of a more complex alias I run when I first open weechat. See /mychannels and /startup, below.
  
  Useful Advanced Aliases
  
  These will build off of some of the aliases we already setup in the “Basic Aliases” section.
  
  Set a ‘work from home’ nick
  - /alias wfh /appendnick wfh
  - Usage:
    
    /wfh
  My nick would now be set to tbielawa|wfh on all logged in servers. Requires you made the /appendnick alias already.
  
  Set a ‘lunch’ nick
  - /alias lunch /appendnick lunch
  - Usage:
    
    /lunch
  My nick would now be set to tbielawa|lunch on all logged in servers.
  
  Set back my normal nick (as if returning from lunch)
  - /alias unlunch /allserv nick tbielawa
  - Usage:
    
    /unlunch
  My nick would now be set back to ‘tbielawa’ on all logged in servers.
  
  Do a Figlet in another buffer
  
  Ask the GCA bot in #it-eng to do a Figlet (Figlets are large ASCII text banners). This works no matter what channel you’re viewing presently, as long as it’s on the same irc network:
  - /alias fig /msg #it-eng gca: figlet $*
  - Usage:
    
    /fig LOLCATS!
  The phrase LOLCATS! will appear in a large ASCII font in the #it-eng channel.
  
  Display three buffers in multiple windows
  
  This requires that you have three horizontally stacked windows open (see /split3 above). It will cycle the focus through each window and then set it to display a specific buffer (channel).
  
  Say for example you automatically join three channels when opening weechat: #it, #secretfunchannel, and #myteamchannel:
  - /alias mychannels /window up; /buffer #it; /window down; /buffer #secretfunchannel; /window down; /buffer #myteamchannel; /window up
  - Usage:
    
    /mychannels
  When the alias finishes the cursor will be focused on the center buffer (channel), which in this example would be #secretfunchannel.
  
  Final Window <-> buffer arrangement after running /mychannels:
  - Top <-> #it
  - Middle <-> #secretfunchannel has the cursor focus
  - Bottom <-> #myteamchannel
  I don’t actually run this alias directly (like /split3, above). It is part of a more complex macro. See /startup, below.
  
  The best alias ever
  
  Sets up your windows and what channels they display correctly when you start weechat. This will split weechat into three horizontally stacked windows, each showing a specific channel:
  - /alias startup /split3; /mychannels
  - Usage:
    
    /startup
  - This alias depends on the /split3 alias and the /mychannels alias, defined above.
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Technitribe

19 Jan 2017

References in a sub-select

Written by Alex Wood

23 Oct 2015

SSL Renewal And You

Written by Tim Bielawa

15 May 2015

Getting consistent fingerprints from git-archive

Written by Alex Wood

16 Mar 2015

Open URL Bug with XDG on XFCE4

Written by Alex Wood

14 Aug 2012

Weechat

Written by Tim Bielawa

Plugins (“Scripts”)

Show the channels you have joined

Direct message notifications

Plugin for opening links in your browser

Built-In Keybindings

Go to the buffer I was last pinged in

Go to buffer #

Go to buffer ##

Moving your cursor focus between split windows

Clear all activity/notification colors from your buffer list

Go up/down channels (“buffers”)

Helpful Custom Key Bindings

Scrolling the user list

User Interface Tweaks

More colors for users nicks

Don’t show every join/part/quit

Fix the buffer titles

Useful Basic Aliases (“slash command” shortcuts)

Set a handle on multiple servers

Close the current buffer (channel window)

Reconnect to multiple networks

Open the last URL posted

Split into three windows

Useful Advanced Aliases

Set a ‘work from home’ nick

Set a ‘lunch’ nick

Set back my normal nick (as if returning from lunch)

Do a Figlet in another buffer

Display three buffers in multiple windows

The best alias ever

Virtual Disk Guide

bitmath

latest posts

tags

h4ck teh world