Archive for the ‘computers/Linux’ Category

Kindle Touch landscape mode – Ubuntu / Linux fix (my solution…)

December 5, 2011

I got my Kindle Touch Wi-Fi with special offers last week. More info on this nice device at the Amazon Kindle Touch page, the Kindle Wikipedia article page, and of course Google searches will do you lots of good.

Granted I’m busy so I’ve not been able to maximize its use yet but I’ve been able to play with it and organize my books and personal documents already. Overall I like the look and feel and functionality of the Kindle Touch (or KT) and I believe you can search reviews with Google, including this good Kindle Touch review by CNET. For reading novels in the native formats accepted by Kindle (e.g. .mobi, .azw files) the pinch-and-zoom as well as the swipe (or just tap) to go to the next/previous page, among other features of KT, are great.

As a researcher though I have lots of PDFs to read, many of which have text formatted in mathematical notation (such as those made using LaTeX). Of course KT can handle PDFs, and even though you could pinch-and-zoom as well as swipe to pan through a page or through pages, reading a PDF  file this way can be really cumbersome especially since the default orientation of viewing in KT is portrait mode. It would be nice if we can rotate the KT to landscape orientation to better read PDF files. However, according to an official statement from a Kindle Customer Support representative, landscape mode is not available on KT. Bummer. I immediately emailed Amazon at kindle-feedback@amazon.com (all of you should! 🙂 ) asking for future software/firmware update to automatically change orientation in KT, and when might this be.

Right now, a sort of “hack” is possible to allow Ubuntu (and other GNU/Linux distros) users like myself to read our PDF books and files in landscape mode in the KT. An answer is to use the pdftk commandline tool which I made a post about some time ago. You can also refer to the man page of your GNU/Linux distribution after installing pdftk. In Ubuntu, a simple and quick apt-get or Synaptic installation should  do the installation job for you (check my post about pdftk above, or search this blog). The “hack” goes like so:

Say you have a PDF file named mydoc.pdf. To rotate the entire PDF file (assuming it is in portrait orientation by default) 90 degrees counterclockwise (so now the mydoc.pdf is now in landscape orientation) fire up a terminal and type:

$ pdftk mydoc.pdf cat 1-endW output tmp.pdf

Where tmp.pdf is the desired output filename of the re-oriented (now in landscape) version of mydoc.pdf. Now you can copy or email the file tmp.pdf to your KT and read your PDF file in landscape mode. 🙂 I’ve yet to check if pdftk works in Mac OS (I won’t be surprised if it does) though I believe this pseudo-hack might turn out to be more “graphical” or point-and-click in nature than my commandline solution above. 🙂 A user from the Amazon KT support page above mentioned using a professional version of Adobe reader to graphically do this, perhaps in Windows and in Mac OS as well. I’d appreciate if somebody would post a link on how to do this graphically in Ubuntu (GNU/Linux), Mac OS, and even in….Windows… 😉 🙂

Happy hacking and Kindling. 🙂

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Find files before/after/in between specific dates

February 14, 2011

Hello folks. \\//,

Well here I am, reading a technical research paper on membrane computing and Petri nets when I decided to download some of the reference materials, conference/journal technical papers, of the paper I’m currently reading.  So I download the reference materials from IEEE Xplore, plus other non-reference materials but still related to the topic I’m reading.

Eventually, I download around 10 PDF files, with filenames made up of purely integers and of course the .pdf extension. Problem is, I’m too lazy (not that much really, I just don’t want to keep doing this manually over and over) to specify each PDF filename, then add them to a compressed archive (this case a RAR file) and then send them to another machine or person or account of mine for archiving.  Essentially, I just want that: to get those PDF files I recently downloaded for this specific topic I’m currently in, not include other PDF files in the same directory, and then compress them into a single RAR file.

How to go over doing this?

Luckily there are for loops and the nifty find command in *nixes like my Ubuntu box. 🙂 So what I simply do is

for i in `find . -type f -cnewer startdate ! -cnewer enddate`; do rar a myrarfile.rar $i; done

which means given 2 reference points, files startdate and enddate, I loop over all files in between the modification times of these two files and then add them to the RAR file myrarfile.rar.

Presto. Problem solved, learned something new. Now, back to reading research papers. 🙂

\\//,

Reference/s:

http://unixhelp.ed.ac.uk/CGI/man-cgi?find

SVN over HTTP

January 31, 2011

Hello there true believers, been a while since I’ve written something here.


A quick FYI on those wanting to use SVN but are restricted to use it from within a network with a proxy.
If you try using SVN over HTTP, it most likely won’t work by default since SVN uses a different network port (usually 3690 for *nixes) and HTTP proxies by default use 80 or 8080 as their ports.
If you try checking out or updating or committing to/from an SVN repo by default, you’ll run into a problem saying SVN couldn’t connect. Uh oh spaghetti-oh. 🙂
In my Ubuntu 10.04 machine, what I do is open (with sudo/root properties) the file:

/etc/subversion/servers

and uncomment (or add, if the following are not present) these parameters:

http-proxy-host = yourproxy.com
http-proxy-port = port

e.g.

http-proxy-host = 10.10.10.10
http-proxy-port = 8080

I save the file, then try SVN again. Voila. I’m back to coding again. 🙂

Reference/s:

Virtualbox shared folder access: Mac OS X host with Ubuntu 10.04 as guest

November 13, 2010

Whew. It’s been a while since I’ve done anything here. 🙂 Now time to do some geeky blogging (and so much more soon) once again mis amigos y amigas. 🙂

Tech specs of the setup

(Host)

Mac OS X Version 10.5.8

$uname -a

Darwin theorylabs-P-System-iMac.local 9.8.0 Darwin Kernel Version 9.8.0: Wed Jul 15 16:55:01 PDT 2009; root:xnu-1228.15.4~1/RELEASE_I386 i386

VirtualBox (non-OSE version, but still free) Version 3.2.10 r66523

(Guest)

Ubuntu Lucid Lynx 10.04 32bit

Setting it up

Essentially just add a shared folder using VirtualBox, whether a VM is running or not. In the guest OS, create a directory where you want your host OS’s files to be mounted (with R or R/W permissions).

Then in the guest OS make sure that the guest additions are successfully installed already. This step is easily and quickly done by mounting the ISO into the guest OS, then allowing Ubuntu 10.04 to detect an autorun script. It will warn you that the running of certain scripts can pose a threat to your system, so we go ahead knowing that the ISO is from Oracle. Otherwise, you can run the script by double-clicking on it or using a terminal.

Once the guest additions have been successfully installed, the following command should mount the host OS’s folder onto the newly created folder in the guest OS which we just created from above:

sudo mount -t vboxsf virtualbox_shared_folder_name guest_os_directory_path

Where virtualbox_shared_folder_name is the name of your host OS’s folder which you entered in the VirtualBox shared folder setting, which may not necessarily be the real directory name of the directory you want to share from your Mac OS X.  guest_os_directory_path is the newly created folder from above awhile ago.

A note on the virtualbox forums, several users say that changing one’s directory in the guest OS to / (root directory of the filesystem) helps, although this wasn’t the case for me.

Hope that helps ladies and gents. Questions are very much welcome. 🙂

Reference/s:

Thoughts on Ubuntu/Kubuntu 9.10

December 2, 2009

After more than a month since Ubuntu/Kubuntu 9.10 codename Karmic Koala was released, here are some thoughts and noteworthy things about it:

Grub2

Ubuntu 9.10, among other recent Linux distros, now uses Grub2. I didn’t read all the release notes, and when I suddenly became curious at taking a look at my menu.lst to see what Grub2 has in store for me, I was in for a surprise. Grub2 doesn’t use menu.lst anymore. It seems menu.lst is already part of legacy Grub. Initially I disliked this, having used menu.lst since I started Linux (6 years ago). The menu.lst has now been superseded by the /boot/grub/grub.cfg file. However, the grub.cfg file is preferably not to be edited by the user, as it is automatically generated by other scripts such as grub-mkconfig. Now I think it’s a good idea to have this boot file editable by a script, which has rigid syntax and rules in order to properly create a boot config file. Of course, nobody is really stopping the hacker inside any of us to not edit the file, nor to create our own menu.lst, or even to revert to legacy Grub versions.

source/s:

Xorg

Ubuntu 9.10 also uses the updated version of Xorg  (as of typing this I use version 1.6.4) doesn’t use an xorg.conf anymore. As Ben Grim/The Thing puts it, “What a revoltin’ development!”. Again initially I was irked by this, but later I also realized it was for the better, since xorg.conf was becoming too cryptic for newer users of Linux. Now the xorg.conf tasks are being handled by several other config files and scripts.

Which got me thinking, since xorg.conf has already been deprecated, what of the ctrl+alt+backspace that we (or at least I) have grown to love when restarting X? It turns out, the ‘dontzap’ option didn’t work anymore, I tried it. The ‘dontzap’ directive worked for 9.04, but apparently not so for 9.10 onwards.  As a result, one way to turn on ‘ctrl+alt+backspace’ back in Kubuntu via graphical method is as follows:

Enabling Ctrl-Alt-Backspace for Kubuntu

  • Click on the Application launcher and select “System Settings”
  • Click on “Regional & Language”.
  • Select “Keyboard Layout”.
  • Click on “Enable keyboard layouts” (in the Layout tab).
  • Select the “Advanced” tab. Then select “Key sequence to kill the X server” and enable “Control + Alt + Backspace”.

Or, for command line folks like me, by doing

setxkbmap -option terminate:ctrl_alt_bksp

source/s:

Deprecation of hal

Several scripts, including devkit-power and devkit-disks are being used as replacements for hal. So far no issues here, and I think so far power as well as disk management in 9.10 is doing great. I do still see hald running in my machine, wonder why that is.

Some caveats and surprises

I’ve had several issues regarding my initial install of Kubuntu 9.10 32 bit desktop. One was Dolphin crashed a few times while I was dragging and dropping files to VLC’s playlist window. These crashes happened in the first 2 to 3 weeks of my installation, regardless of my constant updating of the system. The great thing however is that KDE wallet, coupled with the revamped bug reporting of KDE 4.3.X/Kubuntu 9.10 makes it so much easier to report bugs nowadays. Eat your heart out Micro$oft. 🙂 I do wish they’d fix and close the bug soon. 🙂

I haven’t really been using Konqueror a lot lately since Kubuntu 9.10 now has an ‘Install Mozilla Firefox browser’ option included, even in the live version of the OS, which is nice. In the KDE 3.5.X era I used Konqueror a lot, not as a browser but as a very useful file, ssh, ftp, samba, whathaveyou browser. Nowadays Dolphin is all that except a browser. I can still use Konqueror as my main file browser though, I might try that some time. But I’ve grown to slowly accept Dolphin in my day to day computing tasks. The previews, zoom in/out sliders,  different panels, and the widget make of Dolphin make it a delight to use. So so far no issues with Konquer in 9.10 yet.

Dolphin also makes management of drives a breeze, whether they be internal (IDE, SATA etc.) or external (USB drives, media players etc.). The Oxygen theme also looks very sleek and futuristic.

As with my installation of Ubuntu 9.04, ext4 was a marvel to behold, more so since the 9.10 version uses ext4 by default. Even with apache2 and mysql running at boot, my boot time is well under 30 seconds, even with older single core procs.  Scripts like ureadahead make booting much faster.

Conclusion – for now

Other than perhaps minor setbacks I forgot to mention, plus the introduction of some new technologies I listed above, the 9.10 version of Ubuntu/Kubuntu is a marvelous piece of work, stability, dependability,  and usability wise in my opinion. So far. Can’t wait for 10.04/Lucid Lynx.

IPCop Linux, route command, and network routing

September 16, 2009

This short post is about the dilemma a coworker of mine just had this morning regarding network packets, and a not fully functional IPCop Linux installation.

The Dilemma

The server runs IPCop, which allows a PC to run as a firewall appliance. The IPCop server has 2 NICs, eth0 and eth1. Eth0 is connected to a Class A private LAN while eth1 uses a Class C address to connect to the public Internet. The problem however is that the Internet is accessible (Google, Yahoo! etc.) but not private LAN machines and addresses.  The private LAN’s gateway return ping replies, but not the DNS server.

Detective Work (i.e. Troubleshooting)

What I did was to check all possible causes for this problem: restart the network, checked logs for error messages and others, though some of these had already been done, but I just want to be doubly sure myself. I next checked the firewall using the iptables command. There were tens of lines of firewall rules, along with numerous chains. Since I was in a hurry at that time, I decided to skip the detailed checking of the firewall rules for the moment, even hough I have experience dealing directly with iptables, and not with the higher level application firewalls that just modify it. Next I tried to ping again the DNS server. Adding a -v in the ping command to make it more verbose, I noticed that packets were being successfully sent to the DNS server, but no packets were coming back. I thought to myself that the iptables firewall is one good suspect for this, but I’ll try a few more checks before I go to the nitty gritty of iptables firewall rules. I did ifconfig ethX up and then  down but to no avail. Replace the X with the NIC number you wish to up/down.

The Fix

I next checkd the routing table using the very useful route command. The static IP route looked fine, but I noticed that it was rathe incomplete, given that it has 2 NICs. What I mean by incomplete is that the route from the public, Class C network has routes for going in and out of the destination network and host, but the private LAN doesn’t have a route for traffic going into the IPCop server. It only has a route for traffic coming from the Class A private LAN NIC. Bingo was its name-o. 🙂 Apparently the reason why ping packets weren’t making their way back to the IPCop server was that they weren’t being routed correctly back to the IPCop server itself. This was further supported by using the traceroute command. I traceroute-ed the private LAN DNS server and as expected, the routing of the packet was all messed up. The traceroute packets for the private LAN DNS server were exiting through eth1, and out to the public Internet already. No wonder it doesn’t have a private LAN connection! 🙂

So the fix was to add a correct route to the routing table using the route command. The new route should, well, route the packets correctly from the  private LAN back to the IPCop server, and to make sure that the class A private LAN traffic enters/exits via the eth0 NIC. To do this the command

route add -net NETWORK netmask NETMASK gw GATEWAY

was used. Just replace NETWORK, NETMASK, and GATEWAY with the appropriate values for your network. In our case, NETWORK was the destination host ( the local machine, given by 0.0.0.0) and GATEWAY was the gateway of the Class A network of the private LAN.

Sure enough, after adding that static route, the Class A private LAN became accessible. 🙂

route add -net 192.57.66.0 netmask 255.255.255.0 gw ipx4route add -net 192.57.66.0 netmask 255.255.255.0 gw ipx4

In Linux, no cpu-z you see…

June 22, 2009

… which may be bad at the start, but isn’t so if you really know how powerful Linux is. In this case, you don’t really need to acquire a cpu-z-like software, unless of course you’re freaked out by the command line (which we’ll use in this case).  Linux (at least those that use kernel versions 2.6 and above) have quite  an array of commands that lets you acquire most info that cpu-z will give you on a Window$ box, sometimes less, sometimes more. These commands are especially useful in cases like (this was my case a week ago, that’s why I had to find out about them) there’s no graphical interface for you since you’re either remotely doing administration or the server just doesn’t have any graphical server/service installed.

To list information about the CPU enter the command

cat /proc/cpuinfo

To list your PCI devices type the command

lspci

To acquire information about your installed memory/RAM sticks or modules, one command to do this is

sudo dmidecode —type 17

To check your hard drives, the following commands give you loads of info

cat /proc/diskstats | egrep "^\s?+8"
df -hT
ls -lh /dev/disk/by-path/
ls -lh /dev/disk/by-id/
ls -lh /dev/disk/by-uuid/
cat /proc/scsi/scsi

you then can find out disk info by running the following on each node listed (device name in third column):

sudo fdisk -l /dev/NODE (e.g. sudo fdisk -l /dev/sda, if you have SCSI drives)

There are quite a lot more commands to get information about the hardware you are running, without shutting it/them down so you can open them up and check the hardware yourself. Or you won’t have to grab your hardware’s manual (whether locally or online) just to get info about your hardware. Good especially for sys ads like me. 🙂

Ubuntu, Ubuntu 9.04 Jaunty Jackalope, MSI Wind netbook, and everything in between

April 30, 2009

I just downloaded Ubuntu 9.04 codename Jaunty Jackalope (let’s call it Jaunty for brevity’s sake). I’ve been very occupied the past few days with my morning and afternoon/evening work that’s why it took me this long to sit down and check out Jaunty.  And this post is a quick overview of what’s it like to experience Jaunty, specifically over my MSI Wind U100x.

Aesthetics

Jaunty looks much sleeker and more streamlined than previous Ubuntu incarnations, as shown by the loading splash image.

The login screen has also been revamped and kind of feels more like KDE (which isn’t bad in my opinion).

The geeky stuff

Jaunty gives you the option to install your system using the new ext filesystems, ext4. I tried it out and though I haven’t done any timing tests, the bootup from a clean install seems to be slightly faster. Of course, ext4 has been released for quite a while now and one more reason to use it other than it improves upon the performance of ext3 is that Ubuntu usually never releases/allows untested software (filesystems not the least of these) so you can be pretty sure ext4 is a safe bet. Plus, there’s support from Canonical.

I’m still plowing through Jaunty but the news is that ctrl+alt+backspace, used for restarting the X server, doesn’t work by default. To turn it on, edit your xorg.conf and add:

Option "DontZap" "false"

to the ‘ServerFlags’ section which you should also create/add. The result should look something like

Section "ServerFlags"
    Option         "DontZap" "false"
EndSection

and can also be quickly resolved via a quick Google search. If you want to turn off the restarting effect of ctrl+alt+backspace, then change ‘false’ to ‘true’. More info here.

The boys and girls at the MSI Wind forums have been talking about how Jaunty works in MSI wind. The MSI Wind wiki even has an entry for Jaunty found here, though I must say I didn’t really need much or even all of it to make everything run on my Wind. I’m also quite surprised that that wiki is pretty updated, last updated April 30 when I checked last. The webcam, wi-fi (which is quite surprising since it’s been plagued with problems since Hardy and Intrepid, the 2 previous Ubuntu releases before Jaunty) and others work after a fresh install. Of course for the web cam, you’d have to install a web cam softwaree like Cheese for example, which is readily available in the list of availabe software for download. No config whatsoever as written by the links I gave above. That hassle free setup is kind of scary (at least for me) since I usually like fiddling with my *nix box via the console, but then again nothing is really stopping me right?

Ubuntu 8.04.X (Hardy Heron) wi-fi on Wind

As for making wi-fi run on Hardy, I essentially followed what’s been written here in this part of the MSI Wind forum, particularly this section:

First, you need a proper build environment with the appropriate kernel headers. This is done fairly easily:

Code:
sudo apt-get install build-essential linux-headers-`uname -r`

Next, download and unpack the modified driver sources:

Code:
wget http://scopeboy.com/things/rtl8187se_linux_26.1012.0331.2008_modified.tar.gz
tar xvzf rtl8187se_linux_26.1012.0331.2008_modified.tar.gz

Now build them. Note that you’ll need to set an environment variable in order to avoid a certain problem:

Code:
cd rtl8187se_linux_26.1012.0331.2008
export KBUILD_NOPEDANTIC=1
./makedrv

Now, assuming everything compiled without errors, try starting it all up using the wlan0up script. This will insert the appropriate modules and enable the wireless device. You should then be able to use it with Ubuntu’s network manager.

Code:
sudo ./wlan0up

One other thing to note here is that the person who wrote the piece above was using 8.04.1, and not just 8.04, so it may not necessarily work for you. What you do is just download (from the same forums) the tar.gz driver appropriate for your Hardy version. I myself was using 8.04.2 so I used a .1016.0331 driver package instead of the .1012.0331 shown above. The you can install programs like wi-fi radar (to install it just run ‘apt-get install wifi-radar’) to scope out existing wifi networks around you.

The cool commandline tool I like using is iftop  (apt-get install iftop). The tool iftop shows you what networks/hosts/IP addresses you are connecting to or they to you. It also shows you all the traffic that goes your network card’s way. You run it via

    sudo iftop

which by default let’s you view your first NIC which is usually your wired connection so you do a

    sudo iftop -i wlan0

to view the traffic passing through your wireless card (just replace wlan0 with whatever the command ifconfig gives you as the device name for your wifi card). Then assuming you followed the steps above correctly and you didn’t encounter an error, you should be seeing arrows pointing to and from your IP address coupled with the download and upload speeds (in Bytes, KB or even MB depending on how fast your wireless connection is).

Verdict

So if you really want to stick with Ubuntu’s current LTS (i.e. Hardy) since it gets software updates till 2011, then try the trick above to make your wifi run. Otherwise if you don’t really mind updating your system every 12 months or so, then go for Jaunty. Look and feel and performance is topnotch. So far 🙂 But knowing Ubuntu’s history on software updates and support, plus the huge community and industry support/help you can get, it’s more than enough I think to make you switch from the ‘other’ popular operating system with 4 colors 🙂

Pretty Practicable PDF Tricks In Linux

March 23, 2009

I still don’t have quite a lot of time to write a more or less decent technology or philosophy or science/math related post, but I just want to put this on my blog for the sake of reference  again (as most, if not all, of my blog entries).

My Dilemma

I have a copy of a pdf file from which I want to share some parts only to my lab exercise partner (for reasons I can’t exactly divulge in the public Internet). So I Google around how to manipulate, specifically to  pluck/extract specific pages from a pdf file, and still output the extracted files as pdf file/s themselves. Then I found pdftk. Fantastic tool. Really.

Why Is It Fantastic?

Here are a few reasons why:

For such a small (more or less) package (3408kB in my Ubuntu 8.10 installation) you can:

Pdftk can join and split PDFs; pull single pages from a file; encrypt and decrypt PDF files; add, update, and export a PDF’s metadata; export bookmarks to a text file; add or remove attachments to a PDF; fix a damaged PDF; and fill out PDF forms. In short, there’s very little pdftk can’t do when it comes to working with PDFs.

Also,

Developer Sid Steward describes pdftk as the PDF equivalent of an “electronic staple remover, hole punch, binder, secret decoder ring, and X-ray glasses.”  Pdftk can join and split PDFs; pull single pages from a file; encrypt and decrypt PDF files; add, update, and export a PDF’s metadata; export bookmarks to a text file; add or remove attachments to a PDF; fix a damaged PDF; and fill out PDF forms.

Swiss army knife of PDF files anyone? And thankfully, it’s free and open source. The above quotes are from linux.com, and a lot of us know that once something gets posted on linux.com, it’s more or less worthwhile to learn, more so to read at the very least. pdftk is a command line tool (sorry, but check out my further references below).

And installing it is just simply

sudo apt-get install pdftk

in my Ubuntu 8.04 and 8.10 installations. Again, quoting from linux.com, here are some very useful (at least to me) things you can do with pdftk. Of course, with a bit of knowledge in scripting or programming (bash, php, python etc) you can work wonders with this tool:

Joining files

Pdftk’s ability to join two or more PDF files is on par with such specialized applications as pdfmeld and joinPDF (discussed in this article). The command syntax is simple:

pdftk file1.pdf file2.pdf cat output newFile.pdf

cat is short for concatenate — that is, link together, for those of us who speak plain English — and output tells pdftk to write the combined PDFs to a new file.

Pdftk doesn’t retain bookmarks, but it does keep hyperlinks to both destinations within the PDF and to external files or Web sites. Where some other applications point to the wrong destinations for hyperlinks, the links in PDFs combined using pdftk managed to hit each link target perfectly.

Splitting files

Splitting PDF files with pdftk was an interesting experience. The burst option breaks a PDF into multiple files — one file for each page:

pdftk user_guide.pdf burst

I don’t see the use of doing that, and with larger documents you wind up with a lot of files with names corresponding to their page numbers, like pg_0001 and pg_0013 — not very intuitive.

On the other hand, I found pdftk’s ability to remove specific pages from a PDF file to be useful. For example, to remove pages 10 to 25 from a PDF file, you’d type the following command:

pdftk myDocument.pdf cat 1-9 26-end output removedPages.pdf

Updated Man page

For all the geeks and geekettes out there (no this sub heading is not sexist), here’s an updated man page from my Ubuntu 8.10 server installation:

PDFTK(1)                                                                                                                          PDFTK(1)

NAME
pdftk – A handy tool for manipulating PDF

SYNOPSIS
pdftk <input PDF files | – | PROMPT>
[input_pw <input PDF owner passwords | PROMPT>]
[<operation> <operation arguments>]
[output <output filename | – | PROMPT>]
[encrypt_40bit | encrypt_128bit]
[allow <permissions>]
[owner_pw <owner password | PROMPT>]
[user_pw <user password | PROMPT>]
[flatten] [compress | uncompress]
[keep_first_id | keep_final_id] [drop_xfa]
[verbose] [dont_ask | do_ask]
Where:
<operation> may be empty, or:
[cat | attach_files | unpack_files | burst |
fill_form | background | stamp | generate_fdf
dump_data | dump_data_fields | update_info]

For Complete Help: pdftk –help

DESCRIPTION
If PDF is electronic paper, then pdftk is an electronic staple-remover, hole-punch, binder, secret-decoder-ring, and X-Ray-glasses.
Pdftk is a simple tool for doing everyday things with PDF documents.  Use it to:

* Merge PDF Documents
* Split PDF Pages into a New Document
* Rotate PDF Documents or Pages
* Decrypt Input as Necessary (Password Required)
* Encrypt Output as Desired
* Fill PDF Forms with X/FDF Data and/or Flatten Forms
* Generate FDF Data Stencil from PDF Forms
* Apply a Background Watermark or a Foreground Stamp
* Report PDF Metrics such as Metadata and Bookmarks
* Update PDF Metadata
* Attach Files to PDF Pages or the PDF Document
* Unpack PDF Attachments
* Burst a PDF Document into Single Pages
* Uncompress and Re-Compress Page Streams
* Repair Corrupted PDF (Where Possible)

OPTIONS
A summary of options is included below.

–help, -h
Show summary of options.

<input PDF files | – | PROMPT>
A list of the input PDF files. If you plan to combine these PDFs (without using handles) then list files in  the  order  you
want  them  combined.  Use – to pass a single PDF into pdftk via stdin.  Input files can be associated with handles, where a
handle is a single, upper-case letter:

<input PDF handle>=<input PDF filename>

Handles are often omitted.  They are useful when specifying PDF passwords or page ranges, later.

For example: A=input1.pdf B=input2.pdf

[input_pw <input PDF owner passwords | PROMPT>]
Input PDF owner passwords, if necessary, are associated with files by using their handles:

<input PDF handle>=<input PDF file owner password>

If handles are not given, then passwords are associated with input files by order.

Most pdftk features require that encrypted input PDF are accompanied by the ~owner~ password. If the input PDF has no  owner
password,  then  the  user  password  must be given, instead.  If the input PDF has no passwords, then no password should be
given.

When running in do_ask mode, pdftk will prompt you for a password if the supplied password is incorrect or none was given.

[<operation> <operation arguments>]
If this optional argument is omitted, then pdftk runs in ’filter’ mode.  Filter mode takes only one PDF input and creates  a
new PDF after applying all of the output options, like encryption and compression.

Available operations are: cat, attach_files, unpack_files, burst, fill_form, background, stamp, dump_data, dump_data_fields,
generate_fdf, update_info. Some operations takes additional arguments, described below.

cat [<page ranges>]
Catenates pages from input PDFs to create a new PDF.  Page order in the new PDF is specified by the order  of  the  given
page ranges.  Page ranges are described like this:

<input PDF handle>[<begin page number>[-<end page number>[<qualifier>]]][<page rotation>]

Where  the  handle  identifies one of the input PDF files, and the beginning and ending page numbers are one-based refer‐
ences to pages in the PDF file, and the qualifier can be even or odd, and the page rotation can be N, S, E, W, L,  R,  or
D.

If the handle is omitted from the page range, then the pages are taken from the first input PDF.

The  even  qualifier  causes  pdftk  to  use only the even-numbered PDF pages, so 1-6even yields pages 2, 4 and 6 in that
order.  6-1even yields pages 6, 4 and 2 in that order.

The odd qualifier works similarly to the even.

The page rotation setting can cause pdftk to rotate pages and documents.  Each option sets the page rotation  as  follows
(in  degrees):  N:  0,  E: 90, S: 180, W: 270, L: -90, R: +90, D: +180. L, R, and D make relative adjustments to a page’s
rotation.

If no arguments are passed to cat, then pdftk combines all input PDFs in the order they were given to create the  output.

NOTES:
* <end page number> may be less than <begin page number>.
* The keyword end may be used to reference the final page of a document instead of a page number.
* Reference a single page by omitting the ending page number.
* The handle may be used alone to represent the entire PDF document, e.g., B1-end is the same as B.

Page Range Examples w/o Handles:
1-endE – rotate entire document 90 degrees
5 11 20
5-25oddW – take odd pages in range, rotate 90 degrees
6-1

Page Range Examples Using Handles:
Say A=in1.pdf B=in2.pdf, then:
A1-21
Bend-1odd
A72
A1-21 Beven A72
AW – rotate entire document 90 degrees
B
A2-30evenL – take the even pages from the range, remove 90 degrees from each page’s rotation
A A
AevenW AoddE
AW BW BD

attach_files <attachment filenames | PROMPT> [to_page <page number | PROMPT>]
Packs  arbitrary  files  into  a  PDF  using PDF’s file attachment features. More than one attachment may be listed after
attach_files. Attachments are added at the document level unless the optional to_page option is given, in which case  the
files are attached to the given page number (the first page is 1, the final page is end). For example:

pdftk in.pdf attach_files table1.html table2.html to_page 6 output out.pdf

unpack_files
Copies  all  of  the attachments from the input PDF into the current folder or to an output directory given after output.
For example:

pdftk report.pdf unpack_files output ~/atts/

or, interactively:

pdftk report.pdf unpack_files output PROMPT

burst  Splits a single, input PDF document into individual pages. Also creates a report named doc_data.txt which is the same  as
the  output  from dump_data.  If the output section is omitted, then PDF pages are named: pg_%04d.pdf, e.g.: pg_0001.pdf,
pg_0002.pdf, etc.  To name these pages yourself, supply a printf-styled format string via the output section.  For  exam‐
ple,  if  you  want  pages  named: page_01.pdf, page_02.pdf, etc., pass output page_%02d.pdf to pdftk.  Encryption can be
applied to the output by appending output options such as owner_pw, e.g.:

pdftk in.pdf burst owner_pw foopass

fill_form <FDF data filename | XFDF data filename | – | PROMPT>
Fills the single input PDF’s form fields with the data from an FDF file, XFDF file or  stdin.  Enter  the  data  filename
after fill_form, or use – to pass the data via stdin, like so:

pdftk form.pdf fill_form data.fdf output form.filled.pdf

After  filling  a  form, the form fields remain interactive unless you also use the flatten output option. flatten merges
the form fields with the PDF pages. You can use flatten alone, too, but only on a single PDF:

pdftk form.pdf fill_form data.fdf output out.pdf flatten

or:

pdftk form.filled.pdf output out.pdf flatten

If the input FDF file includes Rich Text formatted data in addition to plain text, then the Rich Text data is packed into
the form fields as well as the plain text.  Pdftk also sets a flag that cues Acrobat/Reader to generate new field appear‐
ances based on the Rich Text data.  That way, when the user opens the PDF, the viewer will create the Rich Text fields on
the  spot.   If the user’s PDF viewer does not support Rich Text, then the user will see the plain text data instead.  If
you flatten this form before Acrobat has a chance to create (and save) new field appearances, then the plain  text  field
data is what you’ll see.

background <background PDF filename | – | PROMPT>
Applies  a  PDF  watermark  to the background of a single input PDF.  Pass the background PDF’s filename after background
like so:

pdftk in.pdf background back.pdf output out.pdf

Pdftk uses only the first page from the background PDF and applies it to every page of  the  input  PDF.   This  page  is
scaled and rotated as needed to fit the input page.  You can use – to pass a background PDF into pdftk via stdin.

If  the input PDF does not have a transparent background (such as a PDF created from page scans) then the resulting back‐
ground won’t be visible — use the stamp feature instead.

stamp <stamp PDF filename | – | PROMPT>
This behaves just like the background feature except it overlays the stamp PDF page on top of the  input  PDF  document’s
pages.  This works best if the stamp PDF page has a transparent background.

dump_data
Reads  a  single, input PDF file and reports various statistics, metadata, bookmarks (a/k/a outlines), and page labels to
the given output filename or (if no output is given) to stdout.  Does not create a new PDF.

dump_data_fields
Reads a single, input PDF file and reports form field statistics to the given output filename or (if no output is  given)
to stdout.  Does not create a new PDF.

generate_fdf
Reads  a single, input PDF file and generates a FDF file suitable for fill_form out of it to the given output filename or
(if no output is given) to stdout.  Does not create a new PDF.

update_info <info data filename | – | PROMPT>
Changes the metadata stored in a single PDF’s Info dictionary to match the input data file. The input data file uses  the
same  syntax  as  the  output from dump_data. This does not change the metadata stored in the PDF’s XMP stream, if it has
one. For example:

pdftk in.pdf update_info in.info output out.pdf

[output <output filename | – | PROMPT>]
The output PDF filename may not be set to the name of an input filename.  Use  –  to  output  to  stdout.   When  using  the
dump_data  operation,  use output to set the name of the output data file. When using the unpack_files operation, use output
to set the name of an output directory.  When using the burst operation, you can use output to  control  the  resulting  PDF
page filenames (described above).

[encrypt_40bit | encrypt_128bit]
If an output PDF user or owner password is given, output PDF encryption strength defaults to 128 bits.  This can be overrid‐
den by specifying encrypt_40bit.

[allow <permissions>]
Permissions are applied to the output PDF only if an encryption strength is specified or an owner or user password is given.
If permissions are not specified, they default to ’none,’ which means all of the following features are disabled.

The permissions section may include one or more of the following features:

Printing
Top Quality Printing

DegradedPrinting
Lower Quality Printing

ModifyContents
Also allows Assembly

Assembly

CopyContents
Also allows ScreenReaders

ScreenReaders

ModifyAnnotations
Also allows FillIn

FillIn

AllFeatures
Allows the user to perform all of the above, and top quality printing.

[owner_pw <owner password | PROMPT>]

[user_pw <user password | PROMPT>]
If  an  encryption  strength  is  given but no passwords are supplied, then the owner and user passwords remain empty, which
means that the resulting PDF may be opened and its security parameters altered by anybody.

[compress | uncompress]
These are only useful when you want to edit PDF code in a text editor like vim or emacs.  Remove PDF page stream compression
by applying the uncompress filter. Use the compress filter to restore compression.

[flatten]
Use  this  option  to merge an input PDF’s interactive form fields (and their data) with the PDF’s pages. Only one input PDF
may be given. Sometimes used with the fill_form operation.

[keep_first_id | keep_final_id]
When combining pages from multiple PDFs, use one of these options to copy the document ID from either  the  first  or  final
input  document  into the new output PDF. Otherwise pdftk creates a new document ID for the output PDF. When no operation is
given, pdftk always uses the ID from the (single) input PDF.

[drop_xfa]
If your input PDF is a form created using Acrobat 7 or Adobe Designer, then it probably has XFA data.  Filling such  a  form
using  pdftk  yields  a PDF with data that fails to display in Acrobat 7 (and 6?).  The workaround solution is to remove the
form’s XFA data, either before you fill the form using pdftk or at the time you fill the  form.  Using  this  option  causes
pdftk to omit the XFA data from the output PDF form.

This  option  is  only  useful  when  running pdftk on a single input PDF.  When assembling a PDF from multiple inputs using
pdftk, any XFA data in the input is automatically omitted.

[verbose]
By default, pdftk runs quietly. Append verbose to the end and it will speak up.

[dont_ask | do_ask]
Depending on the compile-time settings (see ASK_ABOUT_WARNINGS), pdftk might prompt you for further input when it encounters
a  problem, such as a bad password. Override this default behavior by adding dont_ask (so pdftk won’t ask you what to do) or
do_ask (so pdftk will ask you what to do).

When running in dont_ask mode, pdftk will over-write files with its output without notice.

EXAMPLES
Decrypt a PDF
pdftk secured.pdf input_pw foopass output unsecured.pdf

Encrypt a PDF using 128-bit strength (the default), withhold all permissions (the default)
pdftk 1.pdf output 1.128.pdf owner_pw foopass

Same as above, except password ’baz’ must also be used to open output PDF
pdftk 1.pdf output 1.128.pdf owner_pw foo user_pw baz

Same as above, except printing is allowed (once the PDF is open)
pdftk 1.pdf output 1.128.pdf owner_pw foo user_pw baz allow printing

Join in1.pdf and in2.pdf into a new PDF, out1.pdf
pdftk in1.pdf in2.pdf cat output out1.pdf
or (using handles):
pdftk A=in1.pdf B=in2.pdf cat A B output out1.pdf
or (using wildcards):
pdftk *.pdf cat output combined.pdf

Remove ’page 13’ from in1.pdf to create out1.pdf
pdftk in.pdf cat 1-12 14-end output out1.pdf
or:
pdftk A=in1.pdf cat A1-12 A14-end output out1.pdf

Apply 40-bit encryption to output, revoking all permissions (the default). Set the owner PW to ’foopass’.
pdftk 1.pdf 2.pdf cat output 3.pdf encrypt_40bit owner_pw foopass

Join two files, one of which requires the password ’foopass’. The output is not encrypted.
pdftk A=secured.pdf 2.pdf input_pw A=foopass cat output 3.pdf

Uncompress PDF page streams for editing the PDF in a text editor (e.g., vim, emacs)
pdftk doc.pdf output doc.unc.pdf uncompress

Repair a PDF’s corrupted XREF table and stream lengths, if possible
pdftk broken.pdf output fixed.pdf

Burst a single PDF document into pages and dump its data to doc_data.txt
pdftk in.pdf burst

Burst a single PDF document into encrypted pages. Allow low-quality printing
pdftk in.pdf burst owner_pw foopass allow DegradedPrinting

Write a report on PDF document metadata and bookmarks to report.txt
pdftk in.pdf dump_data output report.txt

Rotate the first PDF page to 90 degrees clockwise
pdftk in.pdf cat 1E 2-end output out.pdf

Rotate an entire PDF document to 180 degrees
pdftk in.pdf cat 1-endS output out.pdf

NOTES
pdftk uses a slightly modified iText Java library (http://itextpdf.sourceforge.net/) to read and write  PDF.  The  author  compiled
this Java library using GCJ (http://gcc.gnu.org) so it could be linked with a front end written in C++.

The pdftk home page is http://www.accesspdf.com/pdftk/.

AUTHOR
Sid Steward (ssteward@accesspdf.com) maintains pdftk.

September 18, 2006                                                    PDFTK(1)

Comments, questions, and suggestions are always welcome as long as they’re calm and ruly 🙂

Further References

>>linux.com reference article

>>Main site for pdftk (including manual/documentation), a bit dated though

>> GUI for pdftk

UUIDs, Linux devices, and fstab

November 8, 2008

The Dilemma

I upgraded one of my Ubuntu servers from Hardy Heron (version 8.04 LTS) to Intrepid Ibex (version 8.10). After I rebooted my machine after upgrading my distribution, I noticed that apparently, 8.10 (or at least the kernel used by it initially, 2.6.27-7-generic) fully masks my attached Segate IDE and SATA drives as SCSI drives. My old fstab entries which used IDE raw device names such as /dev/hda1 were no longer relevant. As such, my /home directory had my non-/home SATA hard drive partition mounted on it, for example. I realized ( I don’t know why just now) that using raw device names (e.g. /dev/hda or even /dev/sda) for my mounted drives was a pain in the neck, not only because Ubuntu or the Linux kernel may change sooner rather than later on how to scan, load, mount storage devices. Rather, what is more appropriate is to use the UUIDs of my devices.

Do You UUID?

UUID or universally unique identifier is used around a lot in the tech/computer world these days, e.g. in MAC addresses. It’s basically a 128-bit number or 2128 or approximately 3.4 × 1038, which is a very large number. To put it in perspective, if you would produce oner UUID for every second of every hour of every day, for 365 days a year, you would still need approximately 1 × 1031 years, that’s a 1 with 30 zeros behind it. Now that’s a long time :D. So for now UUIDs are pretty unique, wouldn’t you agree?

Anyway, to get your hard drive’s UUID (whether it’s IDE or SCSI), use either the /dev directory

$ ls -l /dev/disk/by-uuid

to see your devices’ UUIDs. Mine gives

$ ls -l /dev/disk/by-uuid/
total 0
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 46483822-17f9-408b-a3e2-aad688f8380d -> ../../sdd2
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 47AB-8F94 -> ../../sdd1
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 4c05ec57-4171-42c3-b932-f721edc45f15 -> ../../sdd3
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 533bef31-8157-4097-895b-e20217fb90a5 -> ../../sda1
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 5e4cab82-808e-43ec-99a6-bb1a6d7f4efd -> ../../sdc3
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 668cbb68-36a7-4454-bd50-7056f1658a2a -> ../../sdb2
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 71e7e7df-cff4-42ae-a0ec-dddcc6a4dacb -> ../../sdb1
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 b9c011df-1882-4d4c-b215-00ddd7b9bfe0 -> ../../sda3
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 BBF7-94B5 -> ../../sdc1
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 c33271e6-5c7a-406d-a87f-84d9b2d0c196 -> ../../sdc2
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 c3ec0a22-04e8-4735-b6c8-b20e95c2b5a3 -> ../../sda5
lrwxrwxrwx 1 root root 10 2008-11-06 20:28 fdd0b195-0313-4af7-bbbe-9eb1bed89a64 -> ../../sda2

Since I have 4 hard drives and several partitions on those hard drives on my server. The other way to get UUIDs is to use the blkid tool:

$ blkid /dev/sda1
/dev/sda1: UUID=”533bef31-8157-4097-895b-e20217fb90a5″ TYPE=”ext3″

UUIDs come in handy when you want to mount certain plug-and-play or hot-swappable disks onto your machine, and you want to customize the response of your Linux box via /etc/fstab. As for me, UUIDs are very important so I don’t have to depend on raw device names anymore. Instead, I just use my devices’ UUIDs so even if I disconnect and connect them again (assuming I don’t format my hard drives/partitions or intentionally change the assigned UUID Ubuntu assigned to them), I basically get the flexibility that I need.

My previous /etc/fstab looked like this:

UUID=fdd0b195-0313-4af7-bbbe-9eb1bed89a64 /home           ext3    defaults        0       2
# /dev/hda3
UUID=b9c011df-1882-4d4c-b215-00ddd7b9bfe0 none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto,exec 0       0
/dev/hda5       /media/hda5     ext3    defaults        0       2
/dev/sda1       /media/sda1     ntfs-3g uid=1000,umask=007      0       2
/dev/sda2       /media/sda2     ext3    defaults        0       2
/dev/sdc1       /media/sdc1     vfat    uid=1000,umask=007      0       1
/dev/sdc2       /media/sdc2     ext3    defaults        0       2
/dev/sdc3       /media/sdc3     reiserfs        defaults        0       2
/dev/sdb3       /media/sdb3     ext3    defaults        0       2
/dev/sdb1       /media/sdb1     vfat    uid=1000,umask=007      0       1

Now it looks like this (exactly the same hard drive/partition set up):

UUID=fdd0b195-0313-4af7-bbbe-9eb1bed89a64 /home           ext3    defaults,relatime        0       2
# /dev/hda3
UUID=b9c011df-1882-4d4c-b215-00ddd7b9bfe0 none            swap    sw              0       0
#/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto,exec 0       0
UUID=c3ec0a22-04e8-4735-b6c8-b20e95c2b5a3       /media/hda5     ext3    defaults,relatime       0       2
UUID=71e7e7df-cff4-42ae-a0ec-dddcc6a4dacb       /media/sda1     ext3    defaults,relatime       0       2
UUID=71e7e7df-cff4-42ae-a0ec-dddcc6a4dacb       /media/sda2     ext3    defaults,relatime       0       2
UUID=47AB-8F94  /media/sdc1     vfat    defaults        0       2
UUID=46483822-17f9-408b-a3e2-aad688f8380d       /media/sdc2     ext3    defaults,relatime       0       2
UUID=4c05ec57-4171-42c3-b932-f721edc45f15       /media/sdc3     reiserfs        defaults        0       2
UUID=5e4cab82-808e-43ec-99a6-bb1a6d7f4efd       /media/sdb3     ext3    defaults,relatime       0       2
UUID=BBF7-94B5  /media/sdb1     vfat    uid=1000,umask=007      0       1

Now isn’t that prettier? 😀

I just removed the old raw device names and replaced them with the appropriate UUID (e.g. /dev/hda5 is equal to UUID=c3ec0a22-04e8-4735-b6c8-b20e95c2b5a3 ) , and I didn’t have to change the directory where they should be mounted (my /dev/hda5 is mounted at /media/hda5), saving me a lot of time and effort, since I don’t have to update a lot of things dependent on the directory/path where my hard drives are mounted.

Further Reading

* More info on UUIDs and on administration

* The Linux Documentation Project on Linux devices (IDE/SCSI)