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Thursday, September 05, 2013

BASH question

I have a slightly old Ubuntu based distro with a slightly new wifi card that has never had a working wifi driver so I've been having to bake my own. Of course every time a new kernel comes out I have to recompile it with my own wifi driver.

When, say, I'm on a moving train and I update my system, which in turn updates the kernel which then kills my wifi, which then requires me to download the latest headers to re-compile the wifi driver into the kernel, it feels a lot like my own personal hell. I've learned to deal with it by adopting the mantra "dealing with Linux drivers is like going to war armed with a teaspoon".

To save me a lot of pain, I have a BASH script that compiles the driver into the kernel and starts it etc. I also have a custom alias that updates my system, it runs apt-get update, apt-get dselect-upgrade etc, and the second last and important thing it does is download the current kernel headers. I do it with this:

apt-get install linux-headers-`uname -r`

Running this command in a console does the job fine. But within my alias, it seems to grep a whole lot of crap back into it somehow, and I get what feels like a thousand different messages like:

Note, selecting 'libcpan-uploader-perl' for regex 'tree...'

I'd love to know why this happens, I'd probably be able to stop it if I knew why. I'm sure it has something to do with running a sub-command from within an alias. If you know BASH well and can explain this to me I'd greatly appreciate it. I expect most Linux users will ask why the f**k I use BASH and Windows users will ask what the f**k is BASH.

Here are the relevant parts of my ~/.bashrc :

alias nomnomnom='echo Updating repository...
sudo apt-get -yu update
echo Upgrading....
sudo apt-get -yfu dselect-upgrade
echo Updating kernel headers...
sudo apt-get install linux-headers-`uname -r`
echo Cleaning up...
sudo apt-get -yu autoclean
sudo apt-get -yu autoremove
echo Done.

alias fixwifi='echo Shutting down WiFi...
sudo ifconfig wlan0 down
echo Making...
cd /usr/local/src/rtl8723
echo Installing...
sudo make install
echo Restarting WiFi...
sudo modprobe rtl8723e
sudo modprobe -r rtl8723e
sudo modprobe rtl8723e ips=0
sudo ifconfig wlan0 up
echo Done.
sudo ifconfig wlan0

I've come to the conclusion that backticks in an alias are just plain buggy in BASH so I've moved the alias to /blah/bin/nomnomnom and it just works now.