In an email, from is set in the header. To set FROM in any email sent through the mail command, here is the syntax

echo 'Mail body' | \
mail -s 'this is the email subject' -a 'From: sender@example.com' receiver@example.com

A lot of beginners are very much dependent upon phpMyAdmin for their daily work. However a lot of them are not familiar with the basic command line tool like mysql and mysqldump. These two commands can help a lot when I am working on servers without phpMyAdmin installation.

I will show you how to quickly backup and restore database between your local computer and server.

We have a database called dbproject_local which I will migrate to server. The server already has database dbproject_server.

Recently in our office at YIPL, we needed to increase the upload_max_filesize and post_max_size of one of our clients. We run on a virtual private server with WHM and cPanel.

The default php runs as a FastCGI with suexec enabled.

Here is how I configured apache to run custom php.ini.

1. Know where your existing php.ini file exists.

Just create a phpinfo.php file in your public_html or www folder. Use the phpinfo() function know the current location of default php.ini.

/home/username/public_html/phpinfo.php

<?php
phpinfo();
?>

Access the file with http://www.sitename.com/phpinfo.php.

2. Copy the file inside your cgi-bin folder

$ cp /usr/local/lib/php.ini /home/username/public_html/cgi-bin

3. Create a custom cgi executable to run php.

$ vim /home/username/public_html/php.cgi

Add following lines

#!/bin/sh
/usr/local/cpanel/cgi-sys/php5 -c /home/username/public_html/cgi-bin/
# Note, the parameter after -c is the location of new php.ini

Allow executable permission to the new php executable

$ chmod +x /home/username/public_html/cgi-bin/php.cgi

4. Modify .htaccess to run php with our new executable by adding the following lines at the top

$ head /home/username/public_html/.htaccess
Action application/x-httpd-php5 /cgi-bin/php.cgi


#.. other commands

5. Make sure new configuration is loaded.

The http://www.sitename.com/phpinfo.php file should now show /home/username/public_html/cgi-bin/php.ini as the loaded setting file.

6. Remove phpinfo.php for security purposes

$ rm /home/username/www/phpinfo.php

References

• http://drupal.org/node/147534
• http://forums.cpanel.net/f5/fastcgi-fcgid-php-ini-per-user-100133.html

While running a kannel server, I need to make sure certain connections to telcos are up. And here is a simple technique taiyal from ##linux suggested me. It is pretty simple though.

$ netcat -z -w 2 192.168.10.1 5020 -v -n

Netcat is a very simple utility command to connect to a certain ip at certain port. The parameters are as follows.

-z              zero-I/O mode [used for scanning]
-w 2            timeout for connects and final net reads
                in our case try to connect for just 2 seconds
-v              verbose [use twice to be more verbose]
-n              numeric-only IP addresses, no DNS
                No need for dns resolution

Add this to a cron and redirect the output to log file and we're set.

Here is my crontab

$ crontab -e

# m h  dom mon dow   command
*/5 * * * * /home/monitor/bin/checksmsc.sh

And here is my checksmsc.sh code

$ cat /home/monitor/bin/checksmsc.sh
#! /bin/bash
datetime=`date`
log=`netcat -z -w 2 192.168.10.1 5020 -vn 2>&1`
echo $datetime $log >> /home/monitor/log/connection.log

Make sure you make the log folder

$ mkdir /home/monitor/log

Output is in the format as

Sat Jan 30 14:25:02 NPT 2010 (UNKNOWN) [192.80.10.1] 5020 (?) open

Besides netcat, you could also use nmap command

$ nmap 192.168.10.1 -p T:5020 -oG filename.txt

Where -oG specifies output in Greppable format and writes out to filename.txt

Simple tcp monitor :)

The process is a two step process:

First,
Install the required packages
$ sudo apt-get install libavcodec-unstripped-52

Second,
Use proper command line tools for the conversion
$ ffmpeg -i source.wav -acodec libmp3lame -ab 64k destination.mp3

Now although it looks simple, I wasted two hours trying out different tools lame, mencoder, etc and wrong options with ffmpeg. Unnecessary bheja fry!

Cheers