Thanks to antville.org

Upgrade PEAR

shantanuo — Fri, 19 Mar 2010 07:28:23 GMT

I spent a lot of time figuring out how to upgrade my PEAR package.
The trick is to install the PEAR package with –force to make it go through

# pear upgrade --force PEAR

Improve the bash history

shantanuo — Thu, 02 Oct 2008 12:09:04 GMT

If you use two bash sessions at the same time, which ever you close second will write over the commands you’ve typed in the first one. That means that your history is lost for one of the sessions. Annoying to say the least. Luckily there is a way to fix this.

Open your .bashrc file as detailed above and add the lines:

shopt -s histappend
PROMPT_COMMAND='history -a'

This will append any new history to the existing file rather than rewriting it, as well as adding to the history every time the prompt is shown. Now, all your history will be saved!

www.bradshawenterprises.com
_____

If you want to know the date when the command was executed...

$ HISTTIMEFORMAT="%d/%m/%y %T "
OR
$ echo 'export HISTTIMEFORMAT="%d/%m/%y %T "' >> ~/.bash_profile

Counting file types

shantanuo — Mon, 11 Jan 2010 13:13:46 GMT

cat myawk.sh
#!/bin/sh
# list the type of files with count
find ${*-.} -type f -print | xargs file |
awk '{
$1=NULL;
t[$0]++;
}
END {
for (i in t) printf("%d\t%s\n", t[i], i);
}' | sort -nr

show processlist

shantanuo — Tue, 29 Dec 2009 04:20:21 GMT

ps aux
When you run ps you will only get the first 40 or so characters displayed. In order to view the entire string, use ...
ps auxgww

Which Linux?

shantanuo — Wed, 23 Dec 2009 08:52:28 GMT

If you're a Linux expert, Fedora is for you. If you just want a good, general-purpose desktop for home or work, then openSUSE is your best pick. And if you're new to Linux, and your computer gets along well with Ubuntu, Ubuntu is still a good choice.
Knoppix if you want to use Linux off a live CD and puppy linux is for everyone!!

Killing processes

shantanuo — Wed, 23 Dec 2009 08:36:59 GMT

You can enter the "kill" command in a terminal if a process hangs.
kill ID
kill -9 ID
pkill firefox

You can switch to a virtual terminal using Ctrl + Alt + F1 if the user interface does not allow you to start the terminal.
This should hopefully restore some sanity to your computer and you can switch back to the GUI using Ctrl + Alt + F7

vim syntax

shantanuo — Fri, 18 Dec 2009 12:07:54 GMT

behave mswin - Copy and Paste with Ctrl+C CtrlV
set laststatus=2 - grey status bar at the bottom
syntax on - syntax highlighting
set autoindent - auto indenting
set number - line numbers
set showcmd - show command in status line
set showmatch - show matching brackets
set ignorecase - do case insensitive matching
set hlsearch - highlight what you search for

sed can make you sad!

shantanuo — Tue, 11 Aug 2009 15:38:02 GMT

Changing the -e to -i in the following can be disastrous. It will replace the character "g" from all text files found in current directory as well as subfolder.

$ find . -name "*.txt" -exec sed -e 's/g//g' {} \;

Be careful with sed's -i option

___

It can also be very useful to change a string across all files...

select.worldpay.com/wcc/purchase

replace this with the new string

select.wp3.rbsworldpay.com/wcc/purchase/

The command would be...
grep 'select.worldpay.com/wcc/purchase' . -Rl | xargs sed -i 's/select.worldpay.com\/wcc\/purchase/select.wp3.rbsworldpay.com\/wcc\/purchase/g'

Easy SSH

shantanuo — Fri, 18 Dec 2009 09:13:10 GMT

HashKnownHosts no
Add the above line in your ssh_config file that can be found here....
/etc/ssh/ssh_config

Inernal File Separator

shantanuo — Tue, 01 Dec 2009 11:37:01 GMT

The safe way to change IFS in a 'while read' loop is:

while IFS=\| read a b c
do
: whatever
done

Overwriting files

shantanuo — Sat, 21 Nov 2009 11:45:18 GMT

output redirection using n> usually overwrites existing files. You can control this with the noclobber option of the set builtin. If it has been set, you can override it using n>|

$ set -o noclobber
$ ls x* z* >stdout.txt 2>stderr.txt
-bash: stdout.txt: cannot overwrite existing file
$ ls x* z* >|stdout.txt 2>|stderr.txt
$ set +o noclobber

send messages across network

shantanuo — Thu, 19 Nov 2009 13:04:36 GMT

The following command can be used to send messages to remote servers.

ssh -X root@123.123.123.123 'DISPLAY=:0 notify-send "TEST MESSAGE."'

The command that actually sends the message is...
notify-send "hi vandana"

power of wget

shantanuo — Sun, 18 Oct 2009 04:16:07 GMT

wget is really a very powerful utility. Here is an example.

wget -mk oksoft.antville.org

I can download all the pages linked from my blog. And it is so easy!

-m (--mirror) Turn on options suitable for mirroring. This option turns on recursion and time-stamping, sets infinite recursion depth and keeps FTP directory list‐ings. It is currently equivalent to -r -N -l inf --no-remove-listing.

-k (--convert-links) After the download is complete, convert the links in the document to make them suitable for local viewing.

Silence of the Foxes

shantanuo — Sun, 13 Sep 2009 14:00:16 GMT

This simple Firefox tool lets you create custom Firefox installers which you can use to deploy Firefox’s preconfigured settings and add-ons.

www.msfn.org

Zoom in Ubuntu

shantanuo — Sun, 23 Aug 2009 02:19:04 GMT

I can change the tabs in firefox by using Alt + 2 or Alt + 3 or alt + 4 etc. I accidentally found today that Window key + 2 can be used to zoom in! Window key + 1 is for Normal screen size.

Google Calculator

shantanuo — Sun, 16 Aug 2009 07:34:04 GMT

>> 24685316 kb in MB
shows the wrong results:
24 685 316 kilobits = 3 013.34424 megabytes

I should have typed KB in capital to find the correct MB count

>> 24685316 KB in MB
24 685 316 kilobytes = 24 106.7539 megabytes

(Note the spelling difference in kilobits and kilobytes!)

Old date in Shell

shantanuo — Tue, 11 Aug 2009 07:20:01 GMT

If you need to know the 3 days old date, it easy in shell.

$ v_prev_date=`date --date='3 days ago' +%Y%m%d`

$ echo $v_prev_date
20090808

Finding in Linux

shantanuo — Mon, 10 Aug 2009 07:26:40 GMT

I was looking for the file translate.html from my backup drives, e: and f:
Since it was taking some time on Windows system, I stared the live session of Ubuntu and used the following command after touching both the drives from "Places" menu.

find /media/ -name translate.html

Very fast and accurate results!

Number all lines in a file

shantanuo — Sun, 09 Aug 2009 06:46:05 GMT

perl -pe '$_ = "$. $_"'

“-p” causes Perl to assume a loop around the program (specified by “-e”) that reads each line of input into the ” $_ ” variable, executes the program and then prints the ” $_ ” variable. In this one-liner I simply modify ” $_ ” and prepend the ” $. ” variable to it. The special variable ” $. ” contains the current line number of input.
The result is that each line gets its line number prepended.

Ubuntu Root

shantanuo — Sun, 09 Aug 2009 06:05:26 GMT

The root account is disabled by default on Ubuntu installations, mainly to prevent you from doing something you didn’t intend to do.
You can enable root account as follows:

1. Type sudo passwd root and provide a root password.
2. Then head on over to System > Administration > Login Window, go to the Security tab and check “Enable local system administrator login”

You should now be able to login as root from the Login prompt. As an alternative you can use “sudo su” to provide your password and get root prompt.

Starting Ubuntu

shantanuo — Sun, 09 Aug 2009 06:01:13 GMT

You can make Ubuntu remember the applications you had open when you last logged out, so that when you log back in again you’ll find all those applications running and you can resume right from where you left off.

To achieve this go to System > Preferences > Startup Applications, then go to the options tab and check “Automatically remember running applications when logging out”

Export to Excel

shantanuo — Fri, 07 Aug 2009 07:57:11 GMT

Just create a regular .PHP file, where you output your data in a nice little html-table. Then place the following snippet in the top of that file:

header("Content-type: application/vnd.ms-excel");
header("Content-Disposition: attachment; filename=excel.xls");

And it’s just that easy. If you open the page, you’ll see a download-window asking you where to place the file.

Gmail in Firefox

shantanuo — Tue, 07 Jul 2009 14:37:23 GMT

You can set Gmail as Default Email Client in Firefox

* go to Tools > Options
* select the Applications tab
* search for mail
* select Use Gmail from the list of actions associated with the mailto protocol
* click OK to save the settings.

tmpdir in MySQL

shantanuo — Sat, 20 Jun 2009 01:52:21 GMT

In MySQL, the tmpdir path is mainly used for disk-based sorts (if the sort_buffer_size is not enough) and disk-based temp tables.

You can configure a slave with tmpdir=/dev/shm

Install SQLite

shantanuo — Wed, 13 May 2009 13:54:10 GMT

$ # As of March 2009, the latest version was 3.6.11.
$ wget www.sqlite.org
$ tar xzf sqlite-amalgamation-3.6.11.tar.gz
$ cd sqlite-3.6.11
$ ./configure && make
$ sudo make install