Downloading web pages with Downthemall

If you are using firefox to do internet browsing, DownthemAll is a cool plugin.
You install it from here. Once installed , this plugin adds two items to your right click menu. Look at the following picture.




When browsing a web page you can right click and then select the Down them All button. A new window pops up as shown below.


Set up the target diectory and then select the files/URLs to download. Enjoy easy download.

List of installed packages in Ubuntu 8.10

The list of installed packages in Ubunu/ debian can be see by the following command

# dpkg -l

I you want the list of packages along with the disk space they occupy use this variation.

# dpkg-query -W --showformat='${Installed-Size} ${Package}\n' | sort -nr | less

This can be very useful if you install lot of packages and later decide to remove some of them to recover space.

Blocking ads with adbloc extention in firefox

Adblock is a firefox extension which can save lot of internet traffic for you. Don't forget to install it if you have a monthly download limit.
This video shows how to install it.



Alternately you can look at this link

Disassembling programs with dissy

Dissy is a small utility which can be used to disassemble executable programs. It is actually a front end to objdump. On ubuntu objdump is provided by the binutils package.
You can install dissy with

sudo apt-get install dissy.


For trying out dissy, write a small C program as below.
int main()
{
printf("hello\n");
returns 0;
}

Compile it
$ gcc -o hello hello.c

Now invoke dissy as

$ dissy hello

You will get a graphical screen as below.

Hex editors in Ubuntu

Ghex is a cool hex editor that I some times use. You can install ghex like this.

Install it like this.
sudo apt-get install ghex

A menu entry will come under Applications->Programming->Hex Editor
Here is a screen shot of Ghex.



Alternately, you can install khexedit.

sudo apt-get install khexedit


Screen shots of khexedit are shown below.

Official Google Blog: A picture of a thousand words?

Official Google Blog: A picture of a thousand words?

Finding large files on ubuntu/debian

Yesterday our LTSP server which runs on debian suddenly stopped working. After some investigation I found out that free hard disk space on the server was very low. The machine has 500+ accounts. I had to locate big files for back up.

The following code can be used for this.

 
$ find /home/sunil -type f -size +20000k -exec ls -lh {} \; | awk '{ print $8 ": " $5 }'

You can replace /home/sunil with what ever path you want to search. Also you can try changing the size from 20000k( 20MB) to some other value.

Looking at man pages

One of my friends was asking how to look into the correct man page.

The Unix man pages are generally divided into the following sections.

Section     Description
1     General commands
2     System calls
3     C library functions
4     Special files (usually devices, those found in /dev) and drivers
5     File formats and conventions
6     Games and screen savers
7     Miscellanea
8     System administration commands and daemon

You can look in various sections

$ man  5 passwd
$ man 1 passwd

The first command above gives you details about the structure of /etc/passwd, whereas the second command above will give you details about passwd command.
If you want to get all man page sections , you must install the following packages on (
debian/ubuntu)

manpages-dev - Manual pages about using GNU/Linux for development
manpages - Manual pages about using a GNU/Linux system

You can also try installing the package funny_manpages

Exploring the proc diretory on Linux

The /proc directory on ubuntu ( or any other linux ) is an interesting place to look at. See this listing.

sunil@debian:~$ ls /proc
1      2043   23019  31945  6893       devices      key-users   swaps
10     2234   2426   32039  6894       diskstats    kmsg        sys
10003  2239   2471   4      693        dma          loadavg     sysrq-trigger
101    2240   24877  5      7014       driver       locks       sysvipc
1135   2246   24878  591    705        execdomains  meminfo     tty
1292   2247   2508   5934   885        fb           misc        uptime
13872  2248   2509   6      9          filesystems  modules     version
13923  2249   2510   609    969        fs           mounts      vmstat
142    2250   2511   611    acpi       ide          mtrr        zoneinfo
143    2254   2512   6857   asound     interrupts   net
1492   2255   2515   6858   buddyinfo  iomem        partitions
1510   2258   27933  6859   bus        ioports      scsi
1771   2261   27970  6860   cmdline    irq          self
2      22998  27971  6876   cpuinfo    kallsyms     slabinfo
2037   22999  3      6891   crypto     kcore        stat

This directory is not residing on your hard disk. Instead it is a snapshot of things inside your kernel. You can see a lot of numbers in the listing above. These refer to various processes running on the system. There are several files you can peek at in /proc . Look at cpuinfo.

sunil@debian:/proc/6891$ cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 4
model name      : Intel(R) Celeron(R) CPU 2.66GHz
stepping        : 9
cpu MHz         : 2660.155
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc up pni monitor ds_cpl tm2 cid cx16 xtpr lahf_lm
bogomips        : 5325.03

This file give you all the information the currently running kernel has , about your processor.
You can explore the rest of the files to find out a lot of system and network related information.

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