TUD OS Demo CD released

The OS Group of Technische Universität Dresden (TUD:OS) has released a live demo CD of their operating system project. They have been researching on microkerne-based design with focus on real-time and security.

Some highlights of the Demo CD are:

  • A new approach for securing graphical user interfaces called Nitpicker,
  • Multiple virtualized Linux kernels running deprivileged on the L4/Fiasco microkernel,
  • A survey of device driver architectures on microkernel-based systems,
  • The presentation of our virtual-file-system approach,
  • A secure transaction application, Qt3 demo applications, and libSDL-based applications running directly on our custom operating system foundation.

More information – an ISO image, and screenshots are available at the demo CD website
tud+os, microkernel, tud, os

ODOC: cksum

cksum — Computes a CRC (Cyclic Redundancy Check) checksum.


cksum prints the CRC checksum for each file along with the number of bytes in the file. The CRC algorithm is specified by the POSIX Std. It is not compatible with the BSD or System V `sum’ algorithms.


$ cksum file — Prints the Checksum, No of Bytes and filename.

$ cksum file1 file2 — Prints the Checksum, No of Bytes and filename for each file.

Read: man cksum
cksum, crc, linux, gnu/linux, odoc

ODOC: sum

sum — Compute and Check .


sum computes a 16-Bit checksum for each given file(s)/stdin. By default, it computes checksums using an algorithm compatible with BSD sum and prints file sizes in units of 1024-byte blocks.


$ sum file — Print checksum and block counts.

$ sum file1 file2 — Print checksum, block counts and filename.

$ sum -r file — Default. Use BSD sum algorithm (1KB/Block).

$ sum -s file — Use System V sum algorithm (512 bytes/Block).

Read: man sum

sum, odoc, linux, gnu/linux

ODOC: md5sum

md5sum — Compute and Check MD5 Check sums.


md5sum computes a 128-bit checksum/fingerprint/message-digest for each specified file. md5sum can also determine whether a file & checksum are consistent.


$ md5sum file — Compute and print the MD5 checksum of that file.

$ md5sum -c input.txt — Read checksum and filename from the file and validate checksums.

$ md5sum -w -c input.txt — Same as above and warn if the checksums format is wrong in the file.

$ md5sum –status -c input.txt — Indicate the status in exit status code.

Read: man md5sum

md5, md5sum, odoc, linux, gnu/linux

ODOC: shred

shred — Overwrite/Delete a file securely.


Overwrite the specified file repeatedly and remove, in order to make it harder for even very expensive hardware probing to recover the data.


$ shred file — Repeatedly overwrite the file content with random data.

$ shred -v file — Show progress info.

$ shred -n 5 file — Overwrite 5 times instead of the default is 25.

$ shred -x file — Use exact file size. Don’t round off.

$ shred -z file — At the end of shred, overwrite the file with zeros.

$ shred -u file — Overwrite, Truncate and Remove the file.

Read: man shred

shred, odoc, linux, gnu/linux

Linux Dictionary

Found this via Digg which has a huge online dictionary full of Linux terms. There are over 24,700 definitions about everything you wanted to know about linux.
linux, gnu/linux, dictionary

ODOC: tac

tac — Concatenate and Print files in reverse order.


tac copies each file to standard output, reversing the records (lines by default) in each separately. It is doing the reverse function of the CAT command (TAC).


$ tac myfile — Print the file (Line by Line) in reverse order.

$ tac -r -s ‘[^a-zA-z0-9-]’ myfile — Print the file (Word by Word) in reverse order, by passing the Regular expression.

$ tac -r -s ‘.|’ myfile — Print the file (Char by Char) in reverse order.

Read: man tac

tac, cat, odoc, linux, gnu/linux

Python website redesigned

Python LogoPython has a new logo and also has redesigned the website. The new site has a better colors and also has rounded corners. The logo is also new and better than the older one. The site design is also professional looking and a lot more organised than the previous site.

python, website, web+design

ODOC: strings

strings – Print the strings of printable characters in files.


For each file given, strings prints the printable character sequences that are at least 4 characters long & are followed by an unprintable character. Strings is mainly useful for determining the contents of
non-text files.


$ strings /bin/ls — Prints the strings from initialized & loaded sections.

$ strings -a file — Scan the whole file for the strings.

$ strings -f /bin/* | grep Free — Print Filename before each string.

$ strings -t o file — Print the offset within the file before each string [o = octal, x = hex, d = decimal].

$ strings -n 10 file — Print sequences of characters that are at least 10 characters long (Default 4).

NOTE: Write one “Hello World” Program in C and try this command on the binary file(a.out) of that program.

Read: man strings
strings, odoc, linux, gnu/linux

ODOC: lpstat

lpstat — Print CUPS status information


lpstat displays status information about the current jobs, and
printers. When run with no arguments, lpstat will list jobs
queued by the user.


$ lpstat — List jobs queued by the user.

$ lpstat -a — Shows the accepting state of all printer queues.

$ lpstat -d — Show default printer queue.

$ lpstat -p — Shows the printers status.

$ lpstat -r — Shows whether or not the CUPS server is running.

$ lpstat -s — Shows a status summary

$ lpstat -t — Show a detailed status

$ lpstat -u user1 — Shows the print jobs queued by user1.

$ lpstat -v prn1 — Shows printers & what device they are attached to.

Read: man lpstat

Sorry for not posting for a long time. Actually I was busy this week as we had our culturals in our college. Also my mouse was not working. I guess I will buy a new computer. So, have any of you have any suggestions for my new system? Please comment here.

odoc, linux, gnu/linux, lpstat, printer