I’m working on a game and I think I could use some jQuery to make it easier to write. So I visited the jQuery Learning Center to get an overview of the library.
There are lots of examples of the code, but I need to actually write code to see how it works. So I wrote a bunch of code to follow along with the examples that they give. It might be useful to others, so here it is. All of the code is in the php file so if you view source, you will have everything I used.
Working with some existing code to pull data from a MySQL database I ran the following code:
$SQL = "SELECT id FROM `sensors` ";
$SQL .= "WHERE `storage_table` LIKE '$source_temperature_table' ";
$r = $db->query($SQL);
my $src_sensor_id = $r->getNextRow();
print "The id is $src_sensor_id \n";No matter which table I ran this on, I always got 1 as the id. So I tried looking at the value of $r using print $r; and the correct ID was showing up. The reason is that perl is different from other languages that I use when it comes to arrays. When I thought I assigned the only value in $r to $src_sensor_id, what I was really doing was assigning the count of the number of rows in $r to $src_sensor_id. When I printed $r, the print statement printed all of the values in the array $r because that’s how print statements handle arrays.
The correct way to assign the array values in $r to variables is to put parentheses around the list of variables in the array. e.g.
my ($src_sensor_id) = $r->getNextRow();If you have multiple items in the array, separate the variables with commas. e.g.
my ($src_sensor_id, $location, $name) = $r->getNextRow();I’ve been working on a server that has been going offline. I can tell it’s offline because I get an indicator in my mail program that shows that I can’t get mail. The first time it happened we called over to the data center and had them restart everything. That worked for a while but then it happened again. This time we went over to the data center and the server itself was fine. Replacing the switch that connected two servers made the problem go away. A few weeks later, the server went offline again. This time it looked like it was a DDOS. It has been fine ever since, but we wanted to have a better way of knowing that there is an issue than me happening to look at my email program and noticing that I wasn’t getting mail.
One way to see if it is alive is to ping the server every few minutes. If I get no response, then send a text to the owner and an email to me.
I have a couple of cron job on my server running under my crontab that send out notifications by text or email every minute. So I edited the crontab to add another job to its list.
To see the cron jobs, crontab -l -u myuserid. To edit type, crontab -e.
# m h dom mon dow command
*/1 * * * * /home/myuserid/reminder.sh
*/1 * * * * /home/myuserid/ping_remote_server.shHere’s the shell script I wrote to ping the server and send out notifications.
#!/bin/sh
ping -c 1 -q remoteservername.com 1>/dev/null 2>&1;
return_code=$?;
if [ $return_code -ne 0 ]; then
#echo "Failure";
mail -s "Server Down" 8055551212@mobile.mycingular.com myuserid@MyServer.com < /dev/null
fi
I ping it once (-c 1), quietly—since I don’t care about the result (-q) and send the result and any error messages to /dev/null. All I care about is whether it was successful. Every Linux command has an exit status code. You can access it with $?. I only care if the command ran successfully, so I check to see if it is not 0.
I don’t need any details in the text that I send, so I set the subject and grab the content from
I’ve been working with some web pages that were written in 2005. I made some changes, but the page wasn’t displaying the way I wanted. The code has lots of nested tables with DIVs inside tables, so I probably just messed up on opening or closing something. The easiest way to find these kind of mistakes is to validate the code and fix the errors. Because the code is so old, it doesn’t validate as XHTML transitional so there were hundreds of errors. Most of the issues are related to capitalization, but a few are because the tags are not closed. I fixed one file by hand, but since I have lots of files that I am working with, I created this sed script to automate the process.
#### ConvertHTML.sed created 2016-01-09
#### Updated 2016-01-15
#### The global flag g is to be required for multiple occurrences on the same line
#### Sometimes the code is in JavaScript functions, so use single quotes instead of double quotes when replacing
#### TH is part of WIDTH, so need to use < and >
#### SELECT and TABLE are MySQL commands so make sure to use the < and >
s/HTML>/html>/g
s/HEAD>/head>/g
s/TITLE>/title>/g
s/BODY>/body>/g
s/META NAME=/meta name=/g
s/<LINK REL=/<link rel=/g
# Change the case and add the type
s/<SCRIPT LANGUAGE="JavaScript">/<script language="Javascript" type="text\/javascript">/g
s/<SCRIPT/<script/g
s/SCRIPT>/script>/g
#### Tables Be careful with TD, TR, TH, parts are in other tags
s/<TABLE/<table/g
s/<TD/<td/g
s/<TR/<tr/g
s/<TH/<th/g
s/TABLE>/table>/g
s/TD>/td>/g
s/TR>/tr>/g
s/TH>/th>/g
s/COLSPAN/colspan/g
s/ROWSPAN/rowspan/g
s/VALIGN=/valign=/g
s/=TOP/='top'/g
s/=BOTTOM/='bottom'/g
s/=CENTER/='center'/g
s/=top/='top'/g
s/=bottom/='bottom'/g
s/=center/='center'/g
s/ALIGN=/align=/g
s/=RIGHT/='right'/g
s/=LEFT/='left'/g
s/=right/='right'/g
s/=left/='left'/g
s/CELLPADDING/cellpadding/g
s/CELLSPACING/cellspacing/g
s/BORDER/border/g
# Make the tag conform
s/NOWRAP>/nowrap='nowrap'>/g
s/NOWRAP /nowrap='nowrap' /g
s/<HR>/<hr \/>/g
s/<BR>/<br \/>/g
s/<BR\/>/<br \/>/g
s/CENTER/center/g
s/<DIV/<div/g
s/DIV>/div>/g
s/H1/h1/g
s/H2/h2/g
s/H3/h3/g
s/H4/h4/g
s/H5/h5/g
s/H6/h6/g
s/<P/<p/g
s/P>/p>/g
s/CLASS=/class=/g
s/ID=/id=/g
s/STYLE=/style=/g
s/<SELECT/<select/g
s/SELECT>/select>/g
s/<IMG/<img/g
s/ALT=/alt=/g
s/SRC=/src=/g
s/A HREF/a href/g
s/<\/A>/<\/a>/g
s/_NEW/_blank/g
s/<B>/<b>/g
s/<\/B>/<\/b>/g
s/STRONG/strong/g
s/SPAN/span/g
s/<UL/<ul/g
s/UL>/ul>/g
s/<LI/<li/g
s/LI>/li>/g
s/HEIGHT=/height=/g
s/WIDTH=/width=/g
s/SIZE=/size=/g
s/FONT/font/g
s/COLOR=/color=/g
s/TYPE=/type=/g
s/Type=/type=/g
s/VALUE=/value=/g
s/NAME=/name=/g
s/<INPUT/<input/g
s/<FORM/<form/g
s/FORM>/form>/g
s/<OPTION/<option/g
s/OPTION>/option>/g
s/<INPUT/<input/g
s/<TEXTAREA/<textarea/g
s/TEXTAREA>/textarea>/g
s/ROWS/rows/g
s/COLS/cols/g
s/VALUE=/value=/g
s/METHOD=POST/method="post"/g
s/ACTION=/action=/g
s/TARGET=/target=/g
# JavaScript Calls
s/onLoad/onload/g
s/onMouse/onmouse/g
s/onmouseOut/onmouseout/g
s/onmouseOver/onmouseover/g
s/onChange/onchange/g
s/onSubmit/onsubmit/g
s/onClick/onclick/g
s/onError/onerror/g
s/ONERROR/onerror/g
s/cellspacing=\([0-9]*\)/cellspacing=\'\1\'/g
s/cellpadding=\([0-9]*\)/cellpadding=\'\1\'/g
# These can be percent
s/width=\([0-9]*\)%/width=\'\1%\'/g
s/height=\([0-9]*\)%/height=\'\1%\'/g
s/border=\([0-9]*\)%/border=\'\1%\'/g
s/width=\([0-9]*\)/width=\'\1\'/g
s/height=\([0-9]*\)/height=\'\1\'/g
s/border=\([0-9]*\)/border=\'\1\'/g
s/colspan=\([0-9]*\)/colspan=\'\1\'/g
# Should be able to match one or more in the previous with \+ but it isn’t working
s/\'\'\'/\'/g
s/\'\'\"/\"/g
# make the selected tag conform. Mine are in perl statements and conditionals
s/selected\"/selected='selected'\"/g
# Lots of image tags aren’t closed
#s/<img \([0-9a-zA-Z\=\/\.\'\"]*\)>/<img \1 a\/>/g
To run the code, save it in a file—mine is called ConvertHTML.sed, then pipe the output to a temporary file for review.
sed -f ./ConvertHTML.sed original.html converted.html
I recently inherited a system and wanted to be edit all of the website files. I changed the group to admin and added myself to the group. Then I wanted to change all of the directories so I could have access to them, and change all of the file permissions so the group had read-write access and others (including Apache) had only read access. The command to do that is:
sudo chmod -R u+rwX,go+rwX,o-w .
-R recursively change
u+rwX users to read and write, and if it is a directory, also execute
go+rwX same as users for group and others
o-w then remove the write permission for others
. start here