od — Dump files in Octal and other formats.
od (Octal Dump) writes an unambiguous representation of the file in screen. Each line of output consists of the offset in the input, followed by groups of data from the file.
Create a 2 lines text file to test following examples.
$ od myfile — Dump the content and Offset in Octal format.
$ od -a myfile — Dump the content as named char.
$ od -b myfile — Dump the content in octal bytes.
$ od -c myfile — Dump the content in ASCII.
$ od -h myfile — Dump the content in Short Hex.
$ od -w6 myfile — Set output width to 6 Bytes. Default is 16.
$ od -j6 myfile — Skip initial 6 Bytes.
$ od -N6 myfile — Read only 6 Bytes.
$ od -Ad myfile — Show Offset values in decimal.
$ od -Ax myfile — Show Offset values in Hex.
$ od -An myfile — Don’t show the Offset.
Read: man od
od, odoc, linux, gnu/linux
Most of you must have heard about Linux from Scratch – a project project that provides you with step-by-step instructions for building your own custom Linux system, entirely from source code. Here is a similar kind of project, by John Goerzen, the Debian From Scratch.
DFS is really two systems:
- a bootable CD for repairing Linux systems or installing Debian
- the program that generates the CDs that are used for #1
You can also download the ISO images from the DFS site.
debian, linux, gnu/linux, dfs, lfs
Sorry for not posting for a long time. I have been living without my computer for about 2 weeks and I am afraid that I may become mad. I will most probably get my new computer by May 1 or 2. I think I will have an AMD Athlon 3000+ 64bit, 1 Gig of RAM, 120GB harddisk and so on. I wonder what to do till I get my computer.
And by the way, did I mention that tomorrow is my 20th birthday.
eject — Eject the removable media
Eject allows removable media (like CD-ROM, Floppy, Tape, JAZ, ZIP) to be ejected under software control. The command can also control some multi-disc CD-ROM changers, the auto-eject feature supported by some devices, and close the disc tray of some CD-ROM drives.
$ eject — Eject the default device, mostly CD.
$ eject -v — Same as above and show more info.
$ eject /dev/cdrom — Eject CD using device file name.
$ eject -t — Close the drive tray.
$ eject -vt — Same as above and show more info.
Read: man eject
eject, linux, odoc, gnu/linux
su — Run a shell with Substitute User
su allows one user to temporarily become another user. It runs a command with the Real & Effective user id, group id and supplemental groups of a given user. If user not given, it will login as root.
$ su — Run a new shell with root user.
$ su user1 — Run a new shell with user1.
$ su -c ls — Run the command with substitute user.
$ su -f user1 — Fast login (skips startup files).
$ su -p user1 — Preserve the environment variables.
$ su -l user1 — Unset all env variables, change Home dir and run shell startup files.
$ su -s /bin/csh — Run csh shell instead of the user’s default shell.
Read: man su
su, linux, odoc, gnu/linux
Here are some tips which can secure your linux box, especially if you are on the always-on internet connection. Anyway, my system is totally down and I got to buy a new system. I want to know which distro to install on it. Also which distro has out-of-the-box support for SATA hard drives. Any suggestions?
security, linux, gnu/linux,sata
colrm — Remove columns from a file.
colrm removes selected columns from the input. Input is taken from STDIN and Output is sent to STDOUT. Column numbering starts with 1.
$ ls -l | colrm 35 — Remove all columns after the 34th column.
$ ls -l | colrm 1 14 — Remove columns from 1 to 14.
Read: man colrm
colrm, linux, odoc, gnu/linux
Google has announced the Summer of Code this year too. Summer of Code is a program started by Google last year to make more students to develop Free/Open Source Softwares. The students will be aided by organisations which develop Open Source softwares. Each student will be assigned one mentor and will also get stipend. If a student is selected in the program, then Google pays $500 initially. Then during the middle of the program (if sufficient progress has been made), then it pays $2000, and at the end of the program, will pay $2000. The mentoring organisation will also get $500 for every student it helps. So, Google spends $5000 for every student. Last year of the 8744 applicants, 419 students were accepted into the program and more than 80% of them succeeded, which means they received the full stipend of $4500. This year, Google plans to take in more students.
This is a nice oppurtunity for students to showcase their coding skills and also contribute to the open source community – also get paid for it.
google, summer of code, open source, free software
lsmod — Show the status of loaded Linux Kernel Modules.
lsmod is a trivial program, which nicely formats the contents of the
/proc/modules, showing what kernel modules are currently loaded.
$ lsmod -V — Print the version number.
$ lsmod — List all currently loaded Kernel Modules.
Read: man lsmod
lsmod, modules, kernel+modules, linux, gnu/linux
lsusb — List all USB devices
lsusb is a utility for displaying information about all USB buses in the system and all devices connected to them.
$ lsusb — List all USB device details in short form.
$ lsusb -v — List all USB device details in long form.
$ lsusb -vv — List all USB device details in very verbose form.
$ lsusb -t — Show USB device hierarchy as a tree.
- lsusb will collect all USB device info from
- List of all known USB IDs are available in
Read: man lsusb
usb,lsusb, linux, odoc, gnu/linux