I had to update several reverse zone files today, so wrote a quick for-loop in bash to freeze and thaw all the zones. The script parsed the zone file names and reversed them into a proper `d.c.b.a.in-addr.arpa` format. Later I tweaked it with sed to make it more flexible (in order to pass it a full or partial IP address), but ended up using `tac` for the reversing part instead – that’s what it’s made for after all. And if you’re wondering what `tac` stand for, just read `cat` backwards. :-)
Create and Update OTRS Tickets from the Command-Line
I recently wrote a notification script for Centreon / Nagios to create and update tickets in OTRS. The ticket details and OTRS connection settings are all defined on the command-line. The GenericTicketConnector.yml must first be installed in OTRS, and a user (aka “Agent”) created for the script. I used perl’s taint mode, so had to hard-code the various log file locations ($logfile, $csvfile, and $dbfile). The Log::Handler module allows the script to output and log different amounts of activity detail, and the DBD::SQLite module is used to keep a local database of the Ticket ID (from OTRS) and the Problem ID (from Centreon / Nagios) associations — so the OTRS ticket can be updated with follow-up notifications from Centreon / Nagios for the same issue.
Change Passwords with SSH and Expect
A few years ago I was supporting a very diverse environment with Solaris, AIX, and Linux servers; some with password logins, public/private key authentication, and several with SecurID passwords. All accounts were local, passwords expired every three months, and the accounts locked after three failed logins — so you can imagine the mess this created if you didn’t go around every server at least every three months. After I’d accumulated about half a dozen passwords, I wrote an Expect script to login and change my password and wrapped it with a bash script to try every old password I had. Since some servers needed a SecurID number to login, the bash script would pause on those and prompt me for the token before continuing.
Wget with Firefox Cookies
I recently found myself needing to scrape information from a website that uses login credentials. The authentication and session information was available in several cookies, which Wget could use, if the cookies were stored in a plain text file. I used Firefox to login and set the cookies, but Firefox saves it’s cookies in an sqlite data file, which must be exported before Wget can use it. A quick Google search turned up a few possible methods using sqlite3, which I’ve adapted here to use with Wget. I’ve also added some additional (example) code to extract hrefs and print them out, along with the webpage url. The script is called with the target url as the only command line argument.
Conceal Email Address with JavaScript
I wrote this perl script years ago when I needed to include my email address on a webpage, but also conceal it from spam bots and spiders.
#!/usr/bin/perl -w
# /usr/local/bin/esc-mailto.pl
# Conceal email address with javaScript.
# by Jean-Sebastien Morisset (https://surniaulula.com/)
use strict;
my ($email, $text) = @ARGV;
$text = $email if (!$text);
if ($email && $text) {
my $mailto = "<a href=\"mailto:$email\" class=\"esc-mailto\">$text</a>";
$mailto =~ s/(.)/sprintf("%%%x", ord($1))/ge;
print "<script language=\"JavaScript\">document.write(unescape(\"$mailto\"))</script>\n";
} else {
print "syntax: $0 {email_address} [optional_link_text]\n";
exit 1;
}
exit 0;
Beautify Query Strings with Rewrites
Sometimes I’ll work on something just to see what it looks like when it’s done. I guess this Apache rewrite might be something like that — I wanted to change the WordPress search query from /?s=value to /s/value, just to make the URL look a little prettier. :) There are probably a few ways to do this, and if you’d like to share some alternatives, feel free to post a comment.
There are two parts to this problem; The first, executing a search query from an /s/value URL, is easily addressed by a rewrite and proxy command. The second problem — how to rewrite a regular search query, but not a proxied search query — is a little tricker. I decided to add an htproxy hostname to my domain with an IP of 127.0.0.1. Then in a rewrite condition, I check for the htproxy hostname, and skip the rewrite if it’s a proxied request. The htproxy hostname must be included in the website’s Apache config as a ServerAlias.
Update a Dynamic DNS IP with BIND
I wrote the following nsupdate-ddns.sh script to update the dynamic DNS entry for my laptop when switching network locations. There are several ways to execute a script like this automatically (cronjob, startup script, launcher, etc.) — I chose to use Sidekick for Mac OS X, which allows me to execute it when switching locations (either network or physical). This script can also create the private authentication key needed by the DDNS BIND server, and will display some sample configuration values. If you’re setting up a new DDNS BIND server, you can use the examples to configure your dynamic zone file.
Random Password in Perl
Here’s a script I keep in ~/bin/randpwd.pl and use frequently to generate random password strings. It prints an 8 character password by default, but you can also specify a different password length on the command line. I left out the capital letter “o” to avoid confusion with the number zero. ;-)