Ubuntu has a lot of advanced bash completion features that simplify using the shell. For example, when using the ssh command, I can tab complete server names based on my host file and my ssh config file. It turns out that most of this is accomplished with one bash_completion script. This page has a lot of useful information about the Bash shell and also the very useful script. I’ve found that when I use Fedora in the Xinu lab, I am left typing a lot of this stuff myself. Since I use the same bashrc file on both Dakara and my lab machine (Kastria), I didn’t want to always resource the file so I added this to my bashrc:
# Source global definitions
[ -f /etc/bashrc ] && source /etc/bashrc
[ -f /etc/bash.bashrc ] && source /etc/bash.bashrc
# enable programmable completion features
if [ -z "$BASH_COMPLETION" \
-a -r ~/.configuration/bash/bash_completion.caliban ]; then
BASH_COMPLETION=~/.configuration/bash/bash_completion.caliban
source $BASH_COMPLETION
fi
First, I source the global definitions, Ubuntu uses /etc/bashrc, and Fedora uses /etc/bash.bashrc. After that, if the bash_completion script was already sourced, $BASH_COMPLETION will be set. I check to see if it is zero length (-z) and then source my own copy of it if it is. Now I have advanced bash completion on both Ubuntu and Fedora.
Every now and then I feel permitted to go on a rant. It’s unfortunate because this isn’t even a particularly good rant. Why do so many of my (instant messaging) conversations with others about Vim look like this?
Chris: do you use an IDE?
Chris: and if so which one?
Zachary: um, I generally use vim:-P
Chris: gah
Vim is a great text editor. It’s a step up from Ed which is the standard text editor. I started using Vim five years ago. That was about the time that I discovered secure shell, and I started administering servers and other computers remotely. It turns out that Vim was the best text editor over a secure shell session, and since most of my machines ran Mac OS X at the time, Emacs was a terrible option. (I’m not really sure what you call Emacs on Mac OS X. You probably shouldnt’ call it Emacs.) I limped along using very basic Vim functionality over secure shell for a while. Then I discovered a useful graphical tutorial for Vim, and it became considerably more useful.
Now I use Vim because every other text editor or word processor is slower and requires the use of a mouse. (Gah!) I write most of my documents in LaTeX using Vim. I read my email in Mutt and compose emails in Vim. I use Vim almost exclusively to edit code and configuration files on my workstations and servers which works well because it does a good job of syntax highlighting and smart indentation.
A few years ago, I wouldn’t have thought I’d be using Vim exclusively, and it was somewhat by accident that I switched, but now that I am using it, I would be unable to go back.
I find it very annoying when I paste text into a Vim, and it decides to re-tab everything and comment all lines after a comment. I decided to see if I could find a solution because “:set nosi noai” doesn’t do the trick. Stack Overflow has a solution that works very well:
<Esc> :set paste
<paste all you want>
<Esc> :set nopaste
It’s such a simple solution for a problem that has annoyed me for quite a while.
Since I am running this blog on my own server, I decided I should probably set up some log parsing. My personal website is hosted by Nearly Free Speech, and they provide AWStats for statistics. Another site I administer is hosted by DreamHost. DreamHost provides Analog web statistics. After playing with both, I decided to use AWStats.
Ubuntu Tutorials has provided a nice tutorial about setting up AWStats on Ubuntu. I configured my sites individually with no default site in the following files:
/etc/awstats/awstats.blog.lundscape.com.conf
/etc/awstats/awstats.claude.zacintosh.com.conf
/etc/awstats/awstats.wiki.lundscape.com.conf
This means that browsing to “http://domain.tld/awstats/awstats.pl” as they suggest won’t work. Instead, I append the site to the end of the string like this: “http://domain.tld/awstats/awstats.pl?config=blog.lundscape.com”.
Also, rather than adding entries to my crontab, I simply added a script to my “/etc/cron.hourly”:
#! /bin/bash
/usr/lib/cgi-bin/awstats.pl -config=blog.lundscape.com \
-update > /dev/null 2>&1
/usr/lib/cgi-bin/awstats.pl -config=claude.zacintosh.com \
-update > /dev/null 2>&1
/usr/lib/cgi-bin/awstats.pl -config=wiki.lundscape.com \
-update > /dev/null 2>&1
This automatically updates my AWStats every hour whether I view my statistics in a web browser or not.
My mother needed the latest version of Flash to view a web page. I decided this was a good opportunity to install the package from the command line over secure shell. She has a PowerMac G4 running Mac OS X 10.4. It turns out that the update didn’t work, but I relearned a bit about some useful command line tools for Mac OS X. I always start in the temp directory. Then I downloaded the installer and unzipped it. That’s all pretty straightforward.
cd /tmp/
curl -O http://fpdownload.macromedia.com/get/flashplayer/current/install_flash_player_osx_ub.dmg.zip
unzip install_flash_player_osx_ub.dmg.zip
Next, I used “hdiutil” to mount the disk image and then changed to that directory.
hdiutil attach Install\ Flash\ Player\ 10\ UB.dmg
cd /Volumes/Install\ Flash\ Player\ 10\ UB/
Then I used “installer” to install the package specifying the package with “-pkg Adobe\ Flash\ Player.pkg” and the target volume with “-target /”.
installer -verbose -pkg Adobe\ Flash\ Player.pkg -target /
It will run through the installation and output some information. After that, I changed back to the temp directory. I initially tried using “umount” to unmount the disk image, but that is a bad idea because it doesn’t fully unmount the image. The better approach is to use the “hdiutil” again. I find the volume to unmount by using the “df” command. Once it is unmounted, I deleted the zip file and the disk image.
cd /tmp/
hdiutil detach $(df | grep Flash | awk '{print $1}')
rm install_flash_player_osx_ub.dmg.zip
rm Install\ Flash\ Player\ 10\ UB.dmg
Most applications for Mac OS X come in disk images, and many of those have package installers. This is a quick way to install software on a remote Macintosh or a way to automate installations with scripts.
A while back, I updated one of my servers (Abydos) from Ubuntu 8.0.4 Server to Ubuntu 8.10 Server. That process was pretty easy, but when I rebooted, it failed to boot. I simply selected another kernel version from the boot menu and forgot about it. Then Ben ran into the same issue when he updated his desktop (Loki). I decided to learn a little bit about Grub.
It turns out that fixing the problem is pretty simple. The file to change is /boot/grub/menu.lst, and it contains a default line:
default 0
and a bunch of title lines:
title Ubuntu 8.10, kernel 2.6.27-9-generic
title Ubuntu 8.10, kernel 2.6.27-9-generic (recovery mode)
title Ubuntu 8.10, kernel 2.6.24-19-generic
title Ubuntu 8.10, kernel 2.6.24-19-generic (recovery mode)
title Ubuntu 8.10, memtest86+
Grub uses zero based indexing, so I changed default from 0 to 2. It’s as simple as that.
Recently, I wanted to install a program in my home bin directory, and it had a man page to go with it. I started looking for a way to create my own personal man directory. According to the manual page for man, “man uses a sophisticated method of finding manual page files.” Indeed it does. It turns out that all I had to do was create a man directory inside of my home directory and man would know it was there:
zac@dakara:~$ manpath
/usr/local/man:/usr/local/share/man:/usr/share/man
zac@dakara:~$ mkdir man
zac@dakara:~$ manpath
/home/zac/man:/usr/local/man:/usr/local/share/man:/usr/share/man
Then to install the man page, I simply had to create the appropriate directory structure and copy the man page in:
zac@dakara:~$ mkdir -p man/en/man1/
I recently discovered that I can add an SSH key to an SSH agent on a different machine. I find this useful because I am very protective of my SSH keys and prefer to keep them on my desktop (Dakara) and not on my laptop (Adria).
On Adria, you can see that I have no keys added:
zac@adria:~$ ssh-add -l
The agent has no identities.
I then secure shell to Dakara and forward my agent (-A) from Adria. I still have no keys added:
zac@adria:~$ ssh dakara -A
zac@dakara's password:
No mail.
Last login: Mon Feb 9 17:30:49 2009 from adria.lund
zac@dakara:~$ ssh-add -l
The agent has no identities.
Next, I add a key from Dakara to my agent on Adria:
zac@dakara:~$ ssh-add
Enter passphrase for /home/zac/.ssh/id_dsa:
Identity added: /home/zac/.ssh/id_dsa (/home/zac/.ssh/id_dsa)
zac@dakara:~$ ssh-add -l
2048 27:81:f8:7f:38:75:6b:ce:95:e4:46:62:02:9c:84:bd /home/zac/.ssh/id_dsa (DSA)
When I log out of Dakara, the key is still available on Adria:
zac@dakara:~$ logout
Connection to dakara closed.
zac@adria:~$ ssh-add -l
2048 27:81:f8:7f:38:75:6b:ce:95:e4:46:62:02:9c:84:bd /home/zac/.ssh/id_dsa (DSA)
Now my key is available on Adria without ever being on Adria. Even with physical access to my laptop, it would take a sophisticated hacker to steal my SSH key.
Welcome to the Lundscape blog. My brother Ben and I plan on using this blog to document our use of the Linux operating system. I made Ubuntu Linux my primary operating system sometime in May, and Ben switched to Ubuntu Linux in August.