Reset screen terminal after printing garbage

When accidentally printing binary data in a terminal the state of the terminal gets messed up and one needs to reset it. When using GNU screen, this is maintaining part of the terminal state as well.

To reset it:
- press Ctrl-A
- enter ":reset" and press enter

Done. You many need to enter "reset" in the terminal itself as well.

rsyslogd does not log kernel messages to kern.log on Ubuntu 14.04.1 and OpenVZ

Problem: Logging dropped packets using iptables LOG policy did not work. Well, the precise problem was, that the messages did not end up in /var/log/kern.log (nor in any other log file), but they did show in 'dmesg' and /proc/kmsg.

This one was tough. Googling showed that this problem could be solved by uncommenting the line '$ModLoad imklog' in /etc/rsyslog.conf. This in turn caused kern.log to be filled with messages like 'imklog: error reading kernel log - shutting down: Bad file descriptor'. This in turn is probably caused by some strange interaction between Ubuntu and OpenVZ/virtualization combination, but initially I did not find the precise cause of the problem, nor a solution.

This link finally gives a clue what the problem is and also presents a working workaround:

http://www.nostate.com/4228/fixing-the-100-cpu-and-no-useful-output-imklogrsyslog-kernel-logging-problem-on-ubuntu-guests-under-xen-pv/

Following the solution worked for me. In more detail:

Create file /etc/init/kmsg-pipe.conf with the following content:

# 

# Ye Olde /proc/kmsg hack by Mike Gogulski 

# from http://www.nostate.com/4228/fixing-the-100-cpu-and-no-useful-output-imklogrsyslog-kernel-logging-problem-on-ubuntu-guests-under-xen-pv 

# 

# This is free and unencumbered software released into the public domain under # the terms of the Unlicense [http://unlicense.org/]. 

# 

description "/proc/kmsg pipe hack for rsyslogd" 

start on started rsyslog 

stop on stopped rsyslog 

respawn 

script 

        mkdir -p /var/run/rsyslogd || true 

        mkfifo /var/run/rsyslogd/kmsg || true 

        chown -R syslog /var/run/rsyslogd || true 

        chmod -R 700 /var/run/rsyslogd || true 

        exec dd bs=1 if=/proc/kmsg of=/var/run/rsyslogd/kmsg 

end script

This effectively creates a shadow copy of /proc/kmsg (using dd and a named pipe) which is accessible by the syslog user.

Then adapt /etc/rsyslog.conf to use this:

echo '$KLogPath /var/run/rsyslogd/kmsg' >> /etc/rsyslog.conf

Then execute the script and restart rsyslogd:

initctl start kmsg-pipe

service rsyslog restart

Now /var/log/kern.log should show kernel messages, for example iptables LOG output.

Reset Toner on Brother MFC-9340CDW

The original Brother toner cartridges for the Brother MFC-9340CDW printer runs out of toner after a programmed amount of toner usage which is of course useless. This is how to reset the toners so you can continue to print for quite some time:

- Close all warning and error message windows and return to the main menu.

- Open the Fax menu

- Mark the '*' Button with a pencil, or just remember where it is. Do not press it. It will disappear in the next step.

- Return to the main menu.

- Open the printer so you can see the toners. 

- Press and hold the hidden '*' button for 7 seconds.

- A toner reset menu appears. Reset the toner in question.

  - Choose K=black, C=cyan, M=magenta, Y=yellow, STR=starter (small), STD=standard, HC=high capacity.

- Close the printer and return to the main menu.

See also https://www.timoschindler.de/brother-mfc-9140cdn-toner-resetten/

Copy multiple lines from Windows Command Prompt (cmd.exe)

Holding down shift while pressing the right mouse button in the selected area copies the text and removes all linefeeds. This is not proper cut/copy/paste of multiple lines, but works for a single long line spanning multiple terminal lines. It is better than nothing.

Visual Studio Intellisense: No focus on suggestions.

For some reason sometime my Intellisense changes behavior every now and then (probably a Linux Keyboard shortcut entered in VS). To fix this:

1. Type something so the Intellisense Popup opens.

2. Press Ctrl+Alt+Space to toggle whether the suggestion should have the focus or not.

Volumio autoplay with NAS (hack)

Goal: Let Volumio 1.55 automatically start playing music automatically after the Raspberry Pi is powered on. The RPi is used completely headless and without any buttons, and while it is fine that I can control it through my phone or a computer, I sometimes just want to start the music on random play by flicking a plain old power switch and nothing more.


After a lot of fiddling with /etc/rc.local I realized that the NAS is mounted only after my commands in rc.local were executed. A sleep may help, but rc.local is killed if you sleep to long ... argh, nasty!




Instead I decided to hardcode the autoplay into the PHP scripts directly. I don't know any PHP, but how hard can it be?




Edit file /var/www/command/player_wrk.php and search for 'WORKER MAIN LOOP'.

Add the following lines before the '// --- WORKER MAIN LOOP --- //' line:




// Autoplay

sleep(5);

$cmd = 'amixer cset numid=3 1';

sysCmd($cmd);

$cmd = 'mpc repeat on';

sysCmd($cmd);

$cmd = 'mpc random on';

sysCmd($cmd);

$cmd = 'mpc consume off';

sysCmd($cmd);

$cmd = 'mpc single off';

sysCmd($cmd);

$cmd = 'mpc play';

sysCmd($cmd);




The amixer line tries to force 3.5mm jack audio output. Not sure this works. Omit it if you use your own DAC or HDMI.

Not sure the sleep(5) is necessary. This is actually not specific for NAS and should work with any source. It should play the playlist which was last active.




I would love to have this in the GUI, but I do not know how to hack that in.




Ah yes. Completely unrelated and just so I do not forget it: To get my TL-WN725N WLAN Dongle working with volumio 1.55 I had to download the firmware for it:

sudo wget https://github.com/lwfinger/rtl8188eu/raw/c83976d1dfb4793893158461430261562b3a5bf0/rtl8188eufw.bin -O /lib/firmware/rtlwifi/rtl8188eufw.bin

Mac OS X telnet escape character on a german keyboard is Ctrl+Ü

The title says it all. To get the telnet escape char (^]) in a Mac OS X Terminal, for example to quit telnet, you have to type Ctrl+Ü on a german keyboard.

Update Samsung SSD 840 EVO firmware on Zotac Linux server (poor read performance of old files).

My Samsung SSD 840 EVO was suffering from the apparently well known problem that 'old' files (files which have been written a long while ago and not touched since) had slow read transfer rates (as low as 5 MBytes/s in places, 29 MBytes/s for some big files I had).

I have a Zotac server without a CD drive, so I needed to run the Samsung Performance Restauration tool. I used the DOS / Mac variant which is a DOS bootable disk which contains the update tool. The easiest way to prepare the USB stick is NOT to use the USB zip provided by Samsung but to use the *.iso file (Samsung_Performance_Restoration.iso) instead:

- Mount the ISO file and get the file ISOLINUX/BTDSK.IMG from it.
- dd the BTDSK.IMG directly onto a USB stick
- boot from the USB stick and follow the instructions

On my Zotac machine when booting from this USB stick I got a couple of broken error messages about not being able to boot from device XYZ, but it booted OK from the stick after a couple of seconds.

The performance restauration procedure took 4.5h for a 1TB SSD (60% full) and about 15h for another 1TB SSD (95% full), so expect this to take some time.

Both SSDs were not erased by the procedure.

Avoid hang of headless Zotac server on Ubuntu Linux reboot. (How to disable the graphical console for grub and the Linux kernel.)

My Zotac server did not reboot without a monitor attached. Booting from power-up did work ok. The graphical console of grub seemed to be the problem. Since I do not use the monitor output at all not setting any graphics mode at all and using the 80x25 default console is fine for me. This is how to disable the graphical grub console:

Edit /etc/default/grub

Uncomment this line:
GRUB_TERMINAL=console

In addition I disabled setting any graphics mode on the Linux kernel and setting the timeout to 1 second.

My /etc/default/grub  file now looks like this:

GRUB_DEFAULT=0

GRUB_HIDDEN_TIMEOUT_QUIET=true

GRUB_TIMEOUT=1

GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`

GRUB_CMDLINE_LINUX_DEFAULT="text nomodeset"

GRUB_CMDLINE_LINUX=""

GRUB_TERMINAL=console

Reboot time: The time between pressing enter after 'reboot' and being logged in again with ssh is 25s.

Copy files using rsync as root when the remote host does not allow root access and ssh is on a different port

• Step 1: Make sure you can execute commands as root on the remote host after logging in, without entering your password. For this there are two alternative options:
• You can allow the user to execute sudo without entring the users password. You can do this by adding the following line to the end of /etc/sudoers:
•      ALL=NOPASSWD: ALL
• You can enter the sudo password in advance once and make sure it is cached between sessions. To make sure it is cached between sessions you must add the '!tty_tickets' option to the Defaults line in /etc/sudoers, and then you must run a dummy command as root:
• Defaults        env_reset,!tty_tickets
• ssh -p PORT -t USER@REMOTE_HOST sudo id
• Step 2: Do the rsync. Override the ssh port. Specify "sudo rsync" as remote rsync command. Target the rsync at the non-root user which can now sudo:
•  sudo rsync -avRe "ssh -p PORT" --rsync-path "sudo rsync" LOCAL_DIR USER@REMOTE_HOST:

Ubuntu Linux: Show network throughput of network device eth0 etc in bytes: iftop -B

By default iftop shows the bandwidth in Bit/s
iftop

To show the bandwidth in Bytes/s
iftop -B

Quit screen on german keyboard

On a german keyboard the key binding for 'quit' on GNU screen does not seem to work for me (on Max OS X). But one can simply invoke the quite command directly through the command mode:

• Ctrl-A : quit

Save screen scrollback buffer to file

Type:

• Ctrl-A : hardcopy -h file.txt

For me this saves a lot of leading blank lines, but this is ok.

Epic Rap Battle: Nerd vs. Geek

Strip PDF restrictions on Mac OS X without any special tools

Assuming you have a PDF which has certain restrictions on it (for example you cannot edit the PDF using Preview in the usual way), but which you can print, this is how you can strip these restrictions from the PDF:

• open the Printer Queue for your Printer
• stop the Queue
• print the PDF
• now you should have a file starting with 'd' under /var/spool/cups which is an unprotected version of your PDF
• in Terminal type sudo cp /var/spool/cups/d* ~/Desktop/d.pdf
• this assumes there is just one file starting with a 'd' which is usually the case. If there are multiple files pick one by one until you have your file.
• in Terminal type sudo chown foo:foo ~/Desktop/d.pdf (replace foo with your actual user name)
• file ~/Desktop/d.pdf does not have any restrictions
• in the Printer Queue delete the print job
• start the Printer Queue

Note that this procedure does not allow you to strip passwords from files which you cannot print without a password. The restricted file must at least allow you to print the file.

Mac OS X Lion: Scan for wireless networks

Mac OS X Lion provides a command line tool to scan for wireless networks and print useful information about the networks:

/System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport -s

Also, to see additional information about the currently active wireless connection hold down the Option key while clicking on the Airport Symbol in the menu bar.

Common bashrc settings

There are my personal preferences. Your preferences may differ.

alias e=jed
alias mv="mv -i"
alias cp="cp -i"
alias rm="rm -i"
complete -r
export LANG=C
export EDITOR=jed
export PATH=$PATH:${HOME}/bin

Zotac Zbox ID18 Linux Server

• Zotac Zbox ID18
• Samsung SSD 840 EVO 1TB
• 4GB RAM (SODIMM 1600)
• Ubuntu 13.10

Samsung SSD firmware update: The process is quite broken:

• download the 'Windows' Firmware update for the 840 EVO
• mount it
• dd the btdsk.img onto a USB stick
• put the USB stick into the Zotac
• change the Zotac BIOS so it boots from the USB stick
• reboot
• ignore all error messages about missing partitions
• eventually the Samsung Firmware Update program comes up
• take note of the Firmware revision
• follow the instructions of the program
• wait
• ignore the message about power cycling the SSD, since you cannot power cycle it in isolation
• ignore the message about the firmware update being unsuccessful
• reboot (still from the USB stick)
• check that you have the new firmware revision
• Linux shows: ata1.00: ATA-9: Samsung SSD 840 EVO 1TB, EXT0BB6Q, max UDMA/133)

The installation of Ubuntu is quite straight forward.

Recommended settings after installation:

• Enable TRIM support and avoid unnecessary writes when reading files and dirs:
• /etc/fstab:
• UUID= /   ext4    discard,noatime,errors=remount-ro 0       1
• Reduce amount of disk space reserved for root from 45GB to 1GB:
• sudo tune2fs /dev/sda1 -m 0.1
• Install sshd:
• sudo apt-get install openssh-server
• Install 'sensors' to check the CPU temp:
• sudo apt-get install lm-sensors
• sudo sensors-detect
• sudo service kmod start
• sensors
• Install 'smartmontools' to see the SSD temp and other interesting data:
• sudo apt-get install smartmontools
• sudo smartctl -x /dev/sda | grep -i 'Current Temp'
• Do not start GUI/X
• edit /etc/default/grub:
• #GRUB_HIDDEN_TIMEOUT=0
• GRUB_TIMEOUT=1
• GRUB_CMDLINE_LINUX_DEFAULT="text"
• sudo jed /etc/default/grub
• sudo update-grub
• I like to install:
• sudo apt-get install jed apcalc screen minidlna openssh-server samba emacs ispell subversion g++ imagemagick
• If you have a couple of minutes:
• sudo apt-get update
• sudo apt-get upgrade
• If you would like to manually TRIM the SSD:
• sudo fstrim -v /
• Install SAMBA:
• sudo apt-get install samba
• see https://help.ubuntu.com/12.04/serverguide/samba-fileserver.html

Example /etc/samba/smb.conf:

[zotti]

    comment = Share on the Zotac

    path = /zotti

    browsable = yes

    guest ok = yes

    read only = no

    create mask = 0777

    veto files = /.*.pdf/.*.jpg/.DS_Store/._.DS_Store/.*.ini/.*.txt/.*.mov/.*.avi/.*.mpg/.*.png/

    delete veto files = yes

    hide dot files = yes

    hide unreadable = yes

jed settings for indent=4, just spaces, line numbers on, sane brace insertion

My favorite jed setting in $HOME/.jedrc

USE_TABS = 0;
LINENUMBERS = 2;
% For the following to work you _must_ comment out any c_set_style() call!
C_INDENT = 4;
C_BRACE = 0;
C_BRA_NEWLINE = 0;
C_Colon_Offset = 0;
C_CONTINUED_OFFSET = 4;
public variable C_Class_Offset = 4;

Brother MFC-7440N Toner empty message

Today I again got the 'toner empty' messages from my Brother MFC-7440N printer, for the second toner cartridge in this printers life. I printed 3639 pages total (new toner since 2506 pages). The printer would not print any page any more (after showing the toner almost empty message for ages).

This time the 'tape across toner window' trick would not work, even with black tape. The 'toner empty' message would only go away after doing this strange procedure which probably resets some internal state so it re-checks the toner state:

Open the front cover, then press the Back (german:Storno) button (the left bottom one of the four round black buttons), then press * 0 0 and then * 1 0. (Do not press 1 or 2 as indicated in the display. This is for the drum.) After this the 'toner empty' and also the 'toner almost empty' messages were gone and I could perfectly print again.

A subset of * 0 0 and * 1 0 might be sufficient. Not 100% sure the black tape is necessary at all.

Now the printer is printing happily and in perfect quality again. Lets see how long. :-)

Mac OS X Desktop Background is gray

One thing which bugged me was that every now and then my desktop background on my Mac Book Pro would turn plain medium gray at tome point. I cannot even tell when this happens. Trying to reset the background image will not help when this occurs.

(I am using an external monitor connected to the Mac Book Pro and I put this configuration to sleep and I turn the monitor off at least once a day. I do not power down or reboot the laptop at all unless absolutely necessary.)

Logging out and back in solves the problem, but is of course tedious. I found a better workaround here: http://reviews.cnet.com/8301-13727_7-57389668-263/os-x-desktop-backgrounds-gray-after-waking-from-sleep/

• open a Terminal 
• type: killall Dock

The background image is managed by the Dock application which automatically restarts when killed. This is of course not a solution, but is a rather easy way to 'fix' this, until it happens again. :-)

Ubuntu 12.04: Boot Windows by default

If you have a dual-boot system with Ubuntu Linux and Windows and you would like to boot Windows by default instead of Ubuntu you will find to useful answers here:
http://askubuntu.com/questions/100232/how-do-i-change-the-grub-boot-order

I was using the GUI option since the manual option requires you to know the index of the Windows entry upfront (index starting at 0, for me Windows was at index 5).
This is what I did:

- Start a Terminal (search for 'Terminal' in one of the topmost icons), then paste/type this into the terminal:
sudo add-apt-repository ppa:danielrichter2007/grub-customizer
(enter password)
sudo apt-get update
sudo apt-get install grub-customizer
grub-customizer
(program comes up)
- click Preferences
- select Windows as default
- Close
- Save
- close the program
- restart to test it, done

Viewing local manpages (files)

When I have an unformatted manpage file like foo.1 I had always big trouble looking at it. man foo.1 and setting the man path using -M did not help, and figuring out the usage of nroff manually is a pain. I found the answer on here which I just bluntly replicate here for my (and potentially your) convenience: http://craiccomputing.blogspot.de/2007/01/viewing-local-man-pages.html Just specify an absolute or relative path to the file, like:

man ./foo.1

CPU Benchmark Intel Core i3-2350M vs Intel Core i7-2820QM

Today I benchmarked my i3 Linux laptop vs my i7 MacBook. The results are what I expected, though I am quite happy about the performance of the 'slow' i3, which is a really cheap Lenovo B570 mainstream notebook.

The benchmarks are of course rather meaningless.

Machines:

• Intel(R) Core(TM) i3-2350M CPU @ 2.30GHz 
• (dual core, 4 cores with hyperthreading, no turbo boost)
• (in a Lenovo B570 M58GMGE, 8GB, Ubuntu 12.04)
• (according to cat /proc/cpuinfo)
• Intel(R) Core(TM) i7-2820QM CPU @ 2.30GHz
• (quad core, 8 cores with hyperthreading, turbo boost up to 3.4GHz)
• (in a MacBookPro8,2, 8GB, Mac OS 10.7.4)
• (according to Temperaturmonitor 4.94)

Benchmark      i3     i7     speedup
g++-4.6        6.8s   3.9s   1.74x
calc           5.7s   4.2s   1.36x
Cinebench CPU  2.22P  4.63P  2.09x (i3 Win7, i7 OSX)
Cinebench GL   12.40  27.90  2.25x (i3 Win7, i7 OSX)
Cinebench CPU  -      1.24   -     (VirtualBox guest Windows 7, host OSX, 1 CPU)
Cinebench CPU  -      4.27   -     (VirtualBox guest Windows 7, host OSX, 8 CPUs)
(s in real time)

Benchmark command lines:

• time make CXX=g++-mp-4.6 OPT=-O3 -j 20 
• compiling streplace 0.9.36
• just 5 parallel objects (does not fill the 8 slots of the i7)
• time calc 'log(fact(11**5))
• single core
• Cinebench 11.5 on Windows 7 SP1 and Max OS X 10.7.4

I support this to the fullness:

Copyright-restriction-free Christmas songs from the Musikpiraten e.V.:
http://cdn.musikpiraten-ev.de/singen-im-advent-2011.pdf

Create Booklet PDF service (Mac OS X)

I used this tool to print an A5 document as booklet with staples and four pages per sheet on Mac:

http://www.macupdate.com/app/mac/21068/create-booklet-pdf-service

This worked for me from Word 2011 on Mac OS X Lion 10.7.1 and probably works for any other program as well as this is a universal PDF service (Create Booklet in the PDF menu button in every print dialog).

Mac OS X Lion Apple Mail: Search does not work

After switching to Lion and importing all my old mails (actually all users) from the time machine backup I found that all old mails were there, but Mail would not find any of the old mails when searching.

This cured the problem for me:
Foe each individual mailbox (Inbox, Sent, all your own mailboxes) do:
Menu (not context menu): Mailbox -> Restore (in german: Postfach -> Wiederherstellen)

Juniper SSL VPN SAM does not work on Mac OS X Lion (10.7)

The reoccurring pattern continues: With every individual new Mac OS X version Apple kills existing VPN solutions for Max OS. This is at least true for Cisco VPN and also for the Juniper SSL PVN.

For the Juniper SSL VPN on Mac OS X Lion (10.7) the symptom for me was that the host checker never was loaded and never came up. The browser would just sit there indefinitely.

To get the Juniper SSL VPN working on Lion I found this solution:

https://discussions.apple.com/message/15760121#15760121

(replicated on this webpage:)

http://superuser.com/questions/322690/how-do-i-access-juniper-networks-secure-access-web-vpn-from-os-x-lion

1) Download and install Pacifist from: http://www.charlessoft.com/Pacifist.dmg
2) Download and Mount JavaForMacOSX10.6Update5 from http://support.apple.com/kb/DL1360
3) Download and Mount JavaForMacOSX10.7 from http://support.apple.com/kb/DL1421
4) Launch Pacifist and select Open Package
5) Select the mounted JavaForMacOSX10.6Update5.pkg
6) Hit install, when it prompts always select "Replace"
7) After it is complete, select Open Package and select the JavaForMacOSX10.7.pkg
8) When it prompts select "Replace"
9) You can copy Safari 5.0.5 from SL or if you do not have access to a SL machine
10) Download and mount Safari 5.0.5 from http://appldnld.apple.com.edgesuite.net/content.info.apple.com/Safari5/041-0564.20110413.Fi9pb/Safari5.0.5SnowLeopard.dmg
11) In Pacifist select Open Package and select the Safari 5.0.5 pkg file
12) This time select Extract and place it onto your desktop
13) Go to the Safari5.0.5SnowLeopard folder on your desktop, inside of that you will see an Applications folder, open that and you will see Safari, you can rename this Safari, I named mine Safari 5.0.5 and copy it to your main Applications folder or whereever you want.
14) Launch this Safari and go to About and make sure it says 5.0.5
15) Try your Secure App Manager.

Essentially you need to install the 10.6 Java and the 10.7 Java and downgrade to Safari 5.0.5 (at least 5.1 does not work).

The above description worked for me. I got a couple of error messages saying that files cannot replace folders, but this seems to be harmless. Just continue with 'Replace'.

Converting Mac/LF encoding to Latin1/LF

I'll never really get the concept behind the surfaces and default surfaces and no surfaces with recode. Anyway, this is how to convert a file with Mac encoding and LF linefeeds into Latin1 encoding and LF linefeeds:

recode mac/..l1 myfile.txt

Or convert UTF-8 to Latin1:

recode utf-8/..l1 myfile.txt

Will we ever be able to get rid of the OS dependent behavior like 'Mac text files have CR lineendings' (which is even wrong since Mac OS X)?

Mac OS X Screen-Sharing: Cut-Copy-Paste

You can cut/copy/paste across to/from your screen sharing session. It just does not share the copy buffer automatically. Instead you need to transfer the copy buffer into either direction explicitly by selecting Edit -> Send copy buffer or Receive copy buffer (the actual english text might be different, you will figure it out). Doing so will not copy or paste anything in itself. You then need to paste on the target side.

For example to transfer from your host to your remote machine:

* copy on host machine 

* Screen-Sharing: Edit->Send copy buffer

* paste on remote machine