random linux notes

motorola Surfboard 6141 making noise

I just want to say despite many nay-sayers posting responses to this on other threads there is something in my SB 6141 that vibrates with uploads. (correlated by noise during speed test).

These two links are have the identical report and then other people trying to argue that it’s not the cable modem. It is the cable modem! It happens with my the use of my phone over wifi, with my computer, laptop, with all the screens and speakers turned off, there are no headphones involved.

I can modulate the sound during an upload by twisting the case. Viewed from from the top of the case, if I twist the top clockwise and the base counter clockwise I can decrease and eliminate the sound.

Really annoying to have a fanless, ssd desktop and a noisy cable modem.

http://ask.metafilter.com/264261/Cable-Internet-Issues-bad-cable-modem

https://geekhack.org/index.php?topic=46563.0

animated gif from imagemagick

put the list of files into a file

ls -1 foo*.jpg > /var/tmp/jpglist

rename randomly named files in numerical order

cat /var/tmp/jpglist|perl -e'$i=1;while ($name=) { chomp $name;$new="week" . $i . ".jpg";system ("cp $name $new");;$i++};'

resize all 13 files named week[number].jpg, add the Week[number].jpg to the lower right hand corner of the file

for file in {1..13} ;do convert -adaptive-resize 256x -gravity SouthEast  -pointsize 30 -annotate 0 "Week $file" week$file.jpg week${file}_sm.jpg; done

stack the jpgs into a animated gif, center the extra vertical space (not all the images are the same height, the tallest image is about 350 pixels).

convert -delay 200 -loop 0 -gravity center -extent 256x350 -coalesce -trim -layers TrimBounds -dispose 2 week[1-9]_sm.jpg week1[0-9]_sm.jpg animated.gif

citrix receiver linux breaks every couple years

and I spend a week looking for the answer – the basic searches lead to dead ends with old articles about server side stuff

searches like

citrix receiver COMODO RSA

don’t help you find the “good stuff”

the good stuff is #5 here:

https://help.ubuntu.com/community/CitrixICAClientHowTo
quoteing for posterity

 
By default, Citrix Receiver only trusts a few root CA certificates, which causes connections to many Citrix servers to fail with an SSL error. The 'ca-certificates' package (already installed on most Ubuntu systems) provides additional CA certificates in /usr/share/ca-certificates/mozilla/ that can be conveniently added to Citrix Receiver to avoid these errors:

sudo ln -s /usr/share/ca-certificates/mozilla/* /opt/Citrix/ICAClient/keystore/cacerts/
sudo c_rehash /opt/Citrix/ICAClient/keystore/cacerts/

ssh authorized_keys not working

make sure SE linux is FSCKING turned off.

vi /etc/sysconfig/selinux # centos – set last line to DISABLED

setenforce 0

wp-login.php

Defending this script has become my biggest nightmare in the last few months. Black listing mostly works for denial of service from poorly written bots. I blacklist amazon, web hosts, many foreign countries, without hesitation, not just one IP but their whole allocation.

Fail2ban was able to block some portion of these but isn’t very flexible or robust so it often missed the boat.

I’d been struggling to keep my server load at reasonable levels due to the constant barrage of hits. When the bot writers got more clever about number of hits per IP per time these methods quickly failed to stem the tide.

Fortunately the ultimate defense is to require a simple webserver password to access wp-login.php. Implementing the following took my sever load back to normal overnight.

# this blerb should work in a .htaccess file or under a virtual host portion of an apache
# config file
#
# Protect wp-login
<Files wp-login.php>
AuthUserFile /home/site_name/.htpasswd
AuthName "Private access"
AuthType Basic
require valid-user
</Files>
#use htpasswd or website tools to create the above .htpasswd file

However many of the wordpress sites on my box use wp-login.php to handle authentication/authorization for private portions of the sites so distributing a second password to all the users didn’t make sense. So a clever use of mod_rewrite was needed for those other sites.

WARNING: You might not be happy if you use the below without adding an additional rule as all your attempts to login will just redirect back to the login page.

<IfModule mod_rewrite.c>
        RewriteEngine On
        RewriteCond %{REQUEST_METHOD} POST
        RewriteCond %{REQUEST_URI} .(wp-login).php*
        RewriteRule (.*) http://%{SERVER_NAME}/$1 [R=301,L]
</IfModule>

editing flac files from the command line

specifically truncating flac files, you can trim off the front of the file with

 flac --skip=0:45 file.flac -o file-short.flac

or trim off the back with

 flac --until=-0:45.5 file-short.flac -o file-short2.flac

virgin mobile samsung galaxy s5 has working FM radio tuner

plug in headphones (antenna), and use nextradio app to control it.

canon multifunction linux 64 bit

the 64 bit driver needs 32 bit libraries, read your install instructions very carefully

14.04 software raid and encryption

I used this as a starting point

http://askubuntu.com/questions/505446/how-to-install-ubuntu-14-04-with-raid-1-using-desktop-installer

I did my own pairs of /boot and / partions on my real disks sda and sdb, then installed mdadm and created the md0 and md1 raids from the command line then ran ubiquity -b

(my /boot is not encrypted, but / is)

used md1 as a encrypted volume which I then mounted as /

#I then used the first guide’s steps to chroot into the new disk, and setup grub
grub-install /dev/sda
grub-install /dev/sdb

#but added steps from
http://blog.asiantuntijakaveri.fi/2014/12/headless-ubuntu-1404-server-with-full.html

to make sure the initrd knew how to mount my encrypted /

#these steps help initrd find my software raid
mkdir -p /dev/md
ln -s /dev/md0 /dev/md/0
ln -s /dev/md1 /dev/md/1
ln -s /dev/md0p1 /dev/md/0p1
ln -s /dev/md1p1 /dev/md/1p1

#make grub easier to deal with
/etc/default/grub (change silent to vervbose, comment out the HIDDEN lines, set the bootwait=10, nosplash, bootdegraded=true

/etc/grub.d/10_linux (set quickboot and quietboot to zero)

add some things to the end of /etc/default/grub

GRUB_TERMINAL_OUTPUT=console
GRUB_TERMINAL=console
GRUB_GFXPAYLOAD=text
GRUB_GFXPAYLOAD_LINUX=keep

#tweaks to get the crypto stuff into initrd
echo “CRYPTSETUP=y” >> /etc/initramfs-tools/initramfs.conf

sed -i -e’s|^setup=”no”$|setup=”yes”|g’ /usr/share/initramfs-tools/hooks/cryptroot

#then rebuild initrd
update-initramfs -c -k all

#then confirm that your initrd has the crypt stuff
lsinitramfs /boot/initrd.img-3.13.0-40-generic | grep cryptroot
lsinitramfs /boot/initrd.img-3.13.0-40-generic | grep cryptsetup

# Update grub.cfg
update-grub

then exit the chroot and umount and reboot

nvidia driver

sudo add-apt-repository -y ppa:xorg-edgers/ppa
sudo apt-get update
sudo apt-get install nvidia-340

e19

sudo add-apt-repository ppa:niko2040/e19
sudo apt-get update
sudo apt-get install enlightenment

amazon prime movies in mozilla

sudo add-apt-repository ppa:mjblenner/ppa-hal
sudo apt-get update
sudo apt-get install hal

netflix just works with a modern chrome

quick and easy pdf editing

GIMP is my new goto for editing pdfs, not as good as the real thing — it edits by drawing graphics over the page — rather than typing in forms on the page — but for filling out basic paper forms it can work well.
1) save pdf
2) open pdf with gimp
3) pick your resolution (100 pixels can work well for basic stuff)
4) draw on or, type on your page
5) export back to pdf — can even overwrite the orig file.