Application Programming Interface on Amit Agarwal Linux Blog

get all the urls in html file (local or on server).

Mon, 17 Feb 2014 10:35:53 +0000

To use this, you will need the lynx tool, so install that first.

sudo yum install lynx

Now, to get list of all the URLs in local html file or some URL, just execute this:

lynx -dump -listonly

Home grown mail scheduler with bash script and cron

Fri, 04 Oct 2013 01:04:35 +0000

If you are using Linux (Fedora/Ubuntu or anything else) then you do get a lot of tools and one of them is cron. Very very useful. Just write some script that can do the task for you, put it in cron and forget it. So, here is a home grown way to schedule mails.

First, copy this script below:

#!/bin/bash -
#===============================================================================
#
#          FILE: sched_mail.sh
#
#         USAGE: ./sched_mail.sh
#
#   DESCRIPTION:
#
#       OPTIONS: ---
#  REQUIREMENTS: ---
#          BUGS: ---
#         NOTES: ---
#        AUTHOR: Amit Agarwal (aka), 
#      REVISION:  ---
#===============================================================================

mailfile="~/mail"
if [[ $(wc -l $mailfile|awk '{print $1}' ) -ge 5 ]]
then
    to=$(grep ^To: $mailfile|sed 's/To: //')
    echo "Good to send mail... to = $to"
    sendmail -t <$mailfile
    echo "once mail is send, delete the contents of file"
    echo "sed -i '4,$ d' $mailfile"
fi

Now, create a file called mail in your home directory, with the following contents:

xmlwf – Is your xml document well formed?

Sat, 18 Feb 2012 06:36:34 +0000

There is a small nifty utility called xmlwf that can check your xml documents to see if they are well formed.

sudo yum install expat

Once installed, simply use :

xmlwf

Need more details, just check the man page 🙂

Assigning ID to Objects transmitted in XML document (stackoverflow.com)
removing characters from php output in xml (stackoverflow.com)
C# XML parsing using XElement and child contents (stackoverflow.com)

client lanman auth is disabled error for samba

Thu, 28 Apr 2011 14:58:30 +0000

The error:

Server requested LANMAN password (share-level security) but ‘client lanman auth’ is disabled

is easily fixable. You just need to tell samba that client lanman auth is enabled. And here is how to do this:

If you are getting this error then add the following in the globals section of the samba configuration:

client lanman auth = Yes

Ensure that you change this in the file /etc/samba/smb.conf

configuration for afraid-dyndns on Fedora and other similar distro.

Fri, 04 Mar 2011 16:42:56 +0000

First install afraid-dyndns with the command:

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      sudo yum install afraid-dyndns
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Now open the configuration file /etc/afraid-dyndns.cfg and we need to change the following:

Notify = root@localhost # leave empty to suppress notifications
CacheFile = /var/cache/afraid-dyndns/IP
AccountHash =

For the Account hash, head over to http://freedns.afraid.org/api/ login and then click one of the XML or the ASCII links there. Once the page has loaded, look at the URL which is of form:

print every nth line

Tue, 01 Mar 2011 13:17:30 +0000

Some time back I was working with lot of data and wanted to analyze only the every 10 line sometimes and sometimes every 20th line. I had to keep doing these changes in vim or otherwise so finally I wrote a program to do this for me. If you need such a program then here it is:

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    <div class="text codecolorer">
      #!/bin/bash -<br /> #===============================================================================<br /> #<br /> #          FILE:  print_nth_line.sh<br /> #<br /> #         USAGE:  ./print_nth_line.sh<br /> #<br /> #   DESCRIPTION:  Print every nth line<br /> #<br /> #       OPTIONS:  ---<br /> #  REQUIREMENTS:  ---<br /> #          BUGS:  ---<br /> #         NOTES:  ---<br /> #        AUTHOR:   (),<br /> #       COMPANY:<br /> #       VERSION:  1.0<br /> #       CREATED:  12/08/2010 05:36:53 PM IST<br /> #      REVISION:  ---<br /> #===============================================================================<br /> <br /> if [ x"$1" == "x" ]<br /> then<br /> echo "Please provide the line numbers to print .. .ex 3 will print 3,6,9"<br /> exit -1;<br /> fi<br /> if [ x"$2" == "x" ]<br /> then<br /> echo "Please provide the filename"<br /> exit -2;<br /> fi<br /> awk 'temp++ { if ( temp % '$1' == 0) print $1};' $2
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analyze debug queries output for wordpress

Wed, 09 Feb 2011 15:25:14 +0000

Some time back, my website became too slow and I started getting timeout response for quite a lot of my pages. When I analyzed things, I found the issue was with the DB queries taking a lot of time. So, I thought of getting my hands dirty and started with installing the plugin “Debug Queries”. Just in case, you don’t know about the plugin, it lists all the queries to DB along with the time taken for the query when a Admin user visits any page.

Empty a file

Sun, 26 Dec 2010 14:56:13 +0000

This one is for those who know the “touch” command. Hope all of us do not follow a command just because it is on one of the popular site without trying to understand the command and the output.

Repeat a portrait eight times so it can be cut out from a 6″x4″ photo and used for visa or passport photos

Fri, 17 Dec 2010 14:41:57 +0000

Repeat a portrait eight times so it can be cut out from a 6″x4″ photo and used for visa or passport photos

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      montage 2007-08-25-3685.jpg +clone -clone 0-1 -clone 0-3 -geometry 500 -frame 5 output.jpg
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  </td>
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Yes, You could do it in the GIMP or even use Inkscape to auto-align the clones, but the command line is so much easier.

intercept stdout/stderr of another process or disowned process

Tue, 23 Nov 2010 12:51:27 +0000

The command is definately going to save your day if you have disowned the process by mistake. Only uses strace so might as well work on Solaris also, though not tried it.

intercept stdout/stderr of another process or disowned process

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      strace -e write=1,2 -p $PID 2>&1 | sed -un "/^ |/p" | sed -ue "s/^.{9 }(.{50}).+/1/g" -e 's/ //g' | xxd -r -p
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Useful to recover a output(stdout and stderr) “disown”ed or “nohup“ep process of other instance of ssh.

Using SQLite to maintain your monthly bills.

Tue, 24 Aug 2010 18:13:54 +0000

I was looking for a small application to maintain my every month bills. The application had to be small and script-able. I basically wanted to keep track of the bills that have been generated and pending payment and the bills that have been paid.

First we will create the <a class="zem_slink" title="Database" rel="wikipedia" href="http://en.wikipedia.org/wiki/Database">database schema with the following command:

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      CREATE TABLE bills(name varchar(20), due_dt text, p_dt text, amount integer);
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  </td>
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So, I built on the knowledge gathered on <a class="zem_slink" title="SQLite" rel="homepage" href="http://sqlite.org/">SQLite. And here is a small script that I wrote:

SQLite – simple use in scripts

Sat, 21 Aug 2010 15:16:31 +0000

Today we will look a the most simple use’s in the scripts and how to use them.

echo ”insert into bills values (”$name”,$date_now, $date_now,$1)”|sqlite bills

or the other way to do this is

<a class="zem_slink" title="SQLite" rel="homepage" href="http://sqlite.org/">sqlite3 bills ”insert into bills values (”$name”,$date_now, $date_now,$1)”

OK, now in the next post we will see a simple application that I am currently developing or planning.<h6 class="zemanta-related-title" style="font-size: 1em;">Related articles by Zemanta <ul class="zemanta-article-ul"> <li class="zemanta-article-ul-li"><a href="http://tobu.lightbird.net/">Tobu Tutorial (tobu.lightbird.net) <li class="zemanta-article-ul-li"><a href="http://go.theregister.com/feed/www.theregister.co.uk/2010/07/02/openoffice_adopts_gstreamer/">OpenOffice gets Ubuntu-media friendly (go.theregister.com) <li class="zemanta-article-ul-li"><a href="http://elegantcode.com/2010/07/02/using-transactionscope-with-sqlite/">Using TransactionScope with SQLite (elegantcode.com) <li class="zemanta-article-ul-li"><a href="http://www.slideshare.net/aikisteve/flash-and-the-city-2010">Flash And The City 2010 (slideshare.net) <div class="zemanta-pixie" style="margin-top: 10px; height: 15px;"><a class="zemanta-pixie-a" title="Enhanced by Zemanta" href="http://www.zemanta.com/"><img class="zemanta-pixie-img" style="border: medium none; float: right;" src="http://img.zemanta.com/zemified_e.png?x-id=7b7c893c-d92b-44bc-8923-d7c6fddc8b42" alt="Enhanced by Zemanta" /><span class="zem-script more-related pretty-attribution">

SQLite : Manager for this simple database

Thu, 19 Aug 2010 07:43:25 +0000

We will look at sqliteman – <a class="zem_slink" title="SQLite" rel="homepage" href="http://sqlite.org/">SQLite Database manager.

If you are looking for a tool for tuning <a class="zem_slink" title="SQL" rel="wikipedia" href="http://en.wikipedia.org/wiki/SQL">SQL statements, manage tables, views, or triggers, administrate the <a class="zem_slink" title="Database" rel="wikipedia" href="http://en.wikipedia.org/wiki/Database">database space and index <a class="zem_slink" title="Statistics" rel="wikipedia" href="http://en.wikipedia.org/wiki/Statistics">statistics then Sqliteman is the perfect choice.
If you are looking for a <a class="zem_slink" title="Graphical user interface" rel="wikipedia" href="http://en.wikipedia.org/wiki/Graphical_user_interface">graphical queries creation wizards, <a class="zem_slink" title="User interface" rel="wikipedia" href="http://en.wikipedia.org/wiki/User_interface">user interface designers for your database, or an universal report tool try the applications designed for tasks such this (<a class="zem_slink" title="Kexi" rel="homepage" href="http://kexi-project.org/">Kexi, knoda).

SQLite – Easy to use, dependable and good to use database for small applications.

Tue, 17 Aug 2010 07:10:19 +0000

For last couple of days I am looking at <a class="zem_slink" title="SQLite" rel="homepage" href="http://sqlite.org/">SQLite, a very footprint, file based Database.

SQLite is a C <a class="zem_slink" title="Library (computing)" rel="wikipedia" href="http://en.wikipedia.org/wiki/Library_%28computing%29">library that implements an <a class="zem_slink" title="SQL" rel="wikipedia" href="http://en.wikipedia.org/wiki/SQL">SQL database <a class="zem_slink" title="Database engine" rel="wikipedia" href="http://en.wikipedia.org/wiki/Database_engine">engine. A large subset of <a class="zem_slink" title="SQL-92" rel="wikipedia" href="http://en.wikipedia.org/wiki/SQL-92">SQL92 is supported. A complete <a class="zem_slink" title="Database" rel="wikipedia" href="http://en.wikipedia.org/wiki/Database">database is stored in a single disk file. The <a class="zem_slink" title="Application programming interface" rel="wikipedia" href="http://en.wikipedia.org/wiki/Application_programming_interface">API is designed for convenience and ease of use. Applications that link against SQLite can enjoy the power and flexibility of an SQL database without the administrative hassles of supporting a separate <a class="zem_slink" title="Database server" rel="wikipedia" href="http://en.wikipedia.org/wiki/Database_server">database server. Version 2 and version 3 binaries are named to permit each to be installed on a single <a class="zem_slink" title="Server (computing)" rel="wikipedia" href="http://en.wikipedia.org/wiki/Server_%28computing%29">host.