Awk and Sed one liners explained

There is an excellent article at OS News here http://www.osnews.com/story/21004/Awk_and_Sed_One-Liners_Explained

Much of the stuff presented there is very useful. However… Yes there is a big “however”. Howevery do you really want to use these platform specific arcane relics that do not have the error handling capabilities needed to handle unexpected scenarios? Short answer… NO.

Use PHP instead. It can do everything awk/sed can much more easily. More importantly you can plan for the unexpected since you get errors back instead of just blindly assuming the awk and sed commands worked as they did in your microcosm of a test world.

Sure PHP is not always installed on the platform. Say you are planning to put your code in a debian package and you are afraid to use PHP since it does not come preinstalled. Well simply put the latest release of PHP as a requirement for your package. Done. Before your package is loaded PHP gets loaded so you have all the wonderful PHP tools and perhaps libraries available.

Then there is the matter of running your code run on windows platforms. Same thing. Require PHP to be installed first. You can find it here for free on the M$ world. Sure there are some cooler languages like python and ruby but they simply are not as solid as PHP nor do they have the excellent pear libraries.

sqlite3

Google gears uses sqlite for it’s client side database. I’ve never used sqlite so I went to the sqlite website. I naturally downloaded all their documentation to file allowing me to browse it offline. All companies should provide this ability. However the documentation only covered C/C++ and TCL.

I really wanted to use PHP but decided to use C/C++ because an example from their site was ready to go. I copied their example but could not compile it. First it was simply locating the proper sqlite3.h file. This was just the start of many errors so I gave up. If it does not work straight out of the box on the latest Ubuntu then there is something very wrong. I googled for C/C++ examples elsewhere but without luck.

So I tried googling for PHP CLI examples under Ubuntu. Not much luck but there was something close at http://www.litewebsite.com/?c=49#sqlite3 so I snagged it. Here it is, modified to run from the command line, so I don’t have to search for a half decent starting example again:


#!/usr/bin/php -q

<?php
//# Much of this I got from:
//# http://www.litewebsite.com/?c=49#sqlite3
//# http://www.devshed.com/c/a/PHP/Working-with-Prepared-Queries-with-PDO-Objects-in-PHP-5/
ini_set('display_errors', 1);
error_reporting(E_ALL & ~E_NOTICE);

function CountFromPage($page) {
try{
$dbh = new PDO('sqlite:pdoTutorial.sqlite3');
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
//$dbh->beginTransaction();
$statement = $dbh->query('SELECT name FROM sqlite_master WHERE type = \'table\'');
$result = $statement->fetchAll();
if( sizeof($result) == 0 ){ // No database tables found? (Will need to refine this check for pageView table only.)
$dbh->exec('CREATE TABLE pageView(id INTEGER PRIMARY KEY AUTOINCREMENT, page CHAR(256), access INTEGER(10))');
}

// insert page visit in database with a prepared statement
$stmt = $dbh->prepare('INSERT INTO pageView (page, access) VALUES (?, ?)');
$stmt->bindParam(1, $page, PDO::PARAM_STR);
$stmt->bindParam(2, time(), PDO::PARAM_INT);
$stmt->execute();

// get page views from database
$pageVisit = $dbh->quote($page);
$sqlGetView = 'SELECT count(page) AS view FROM pageView WHERE page = '.$pageVisit.'';
$result = $dbh->query($sqlGetView);
$pageView = $result->fetch(); // store result in array
//$dbh->commit();
return($pageView['view']);
}catch( PDOException $exception ){
//$dbh->rollBack();
die($exception->getMessage());
}

}

if (2 != $_SERVER["argc"]) {
echo "\tWrong number of arguments:" . $_SERVER["argc"] . "\n";
echo "\tProper syntax is: \n" ;
echo "\t\t" . $_SERVER["argv"][0] . " page\n";
} else {
$page = $_SERVER["argv"][1];
echo 'Page "' . $page . '" has been viewed '. CountFromPage($page).' times.'."\n";
}
?>


I stuck it into a file called 1.php in my samba bin directory as my starting point. This way the database can be shared…

Here is the output when run:

~/samba/bin$ 1.php 11
Page “11″ has been viewed 1 times.
~/samba/bin$ 1.php 11
Page “11″ has been viewed 2 times.
~/samba/bin$ 1.php 12
Page “12″ has been viewed 1 times.
~/samba/bin$ 1.php 12
Page “12″ has been viewed 2 times.
~/samba/bin$ 1.php 11
Page “11″ has been viewed 3 times.