Programs by Anthony Thyssen

Anthony's Castle is his home
Castle's WWW Laboratory
About Anthony Thyssen
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I have made these programs publicly available, and you are free to copy, modify and or re-distribute them. Please do not remove my name from any of them. If you make modifications, please mail them back to me so that others may share them.

Encryption Filters

encrypt: My File Encrypt/Decrypt Program (Perl Script)
Perl program to encrypt/decrypt pipelined file streams using the perl cryptography module Crypt::CBC to do the task with the derived key and IV parameters, much like the "aespipe" C program.

However this version uses the PBKDF v2 password to derive the encryption key from user passphrase. This is a lot safer than simply using the OpenSSL "enc" option to do a 'Salted' file encryption, which does only a single iteration to derive the encryption key from the user provided password. By using PBKDFv2 to iterated the encryion key derivation, you effectively slow down brute force dictionary attacks to impossible speeds, without sacrificing the normal usage of the pass-phrase to encryption key hashing.

I use this for almost all my encryption needs, and have even set up my VIM text editor to call this program when editing encrypted files. Which make it especially useful for personal password files (web passwords), as well as editing "key_files" (see the "ks" script below)

See the script comments for the encrypted file format.

pbkdf2: Access SSL Library PBKDF2 sub-routine (C Program)
A trival program to make the OpenSSL library function PKCS5_PBKDF2_HMAC_SHA1() available on the command line. This is the function that implements the Password Based Key Derivation Function version 2 (PBKDF v2) as per RFC 2898 or PKCS #5.

It was used by the previous "encrypt" script, but is no longer required, as a perl equivelent is now built into the above script.

pbkdf2: Perl Equivelent to PBKDF2 algorithm (Perl Script)
A direct perl implementation of the same program and the C code above. Can be used either as a loadable module, or directly as a perl program. Of course it is slightly slower than the equivalent C program.

I verified that it does indeed generate the same results as the OpenSSL PKCS5_PBKDF2_HMAC_SHA1() function.

This is built into the "encrypt" script above.

Filesystems Mounting and Data Store Encryption

ks: An Encryption Keystore (Perl Script)
A perl script implementing a 'key_store' of multiple 'key_files' containing the master keys and configuration data used to decrypt encrypted data.

The 'key_files' are encrypted using a user supplied password, and contain the actual randomly generated master keys of the real data, as well as the commands, and configuration data needed for the decryption. That is even the 'public' details of the encryption the real data is secured. I don't believe in giving a cracker any hint at all.

The 'key_store' can be physically separated from the actual encrypted data (on USB sticks, or network mounts), making it more secure (two factor). Also fake 'key_files' (name/password pairs) can be added, to the 'key_store'. These fake keys can be made to decrypt other data, or even be made to destory the access to the real data, to further confuse would be attackers, and prevent rubber hose attacks. Basically they can run any command!

This is an in-house key management system that can handle the binary encryption keys needed for ANY encryption scheme. Though it is currently specifically aimed at EncFS data stores, it can be set up (and has been) to handle any encrypted data store, that uses command line controls, and can do so right now.

It is a simple perl script and can be expanded to provide options for the mangement of other types of encrypted data stores, and methods.

Comments welcome.

mount_encrypted: User mount of DM-crypt filesystems (Shell)
With the system "/etc/fstab" setup correctly, you do not need to need to become root to mount a dm_crypt filesystem. This script lets you mount a dm-crypt or luk-crypt encrypted block file systems, with appropriate with password handling for either TTY and X-Windows, as well as good error handling and reporting of any problem encountered.

I previously used this script extensivally from command line, shell scripts, and GUI application launchers, menus, and filesystem mount programs, to mount encrypted filesystems given a user password, without needing root or sudo access.

However its use has since been superseeded by encfs and the "ks" script above. EncFS allows me to directly back up and/or file syncronize the encrypted data between machines without requiring decryption, unlike a disk encrypt method like this.

Files and Paths

cmdout: Label Command Output (Shell Script)
A wrapper around a command which marks the commands output as being from standard output or standard error. Also reports the actual command given and the final exit status of the command.

A useful information gathering about the wrapper program. Especially when you plan to later use that command in a shell script, or for co-processing.

Note getting the exit status of a command while piping its output is generally difficult in older shells. This script is a demonstartion on how this can be achieved.

home_backup: Home Directory Backup (Tar file of Scripts)
A push backup scheme that creates snapshot "rsync" backup of your home directory into a "current" sub-directory directory, on directory or remote account directory given. After a backup (update) is complete, a number of rolling 'cycles' of hardlinked snapshots are created, generating per month, week, day and even hourly snapshots.

A simple "recover" script can be used to list, and restore specific files and directories, from any of the backup 'cycles'.

For more information see Rsync Backups, and Snapshoting

linkdups: Hardlink duplicate files (Perl Script)
Quite a complex perl script that very quickly finds large files that are exact copies of each other. It then hardlinks them together to save disk space.

Files are only size tested initially, with full comparison be performed when a posible match has been found, making this re-hardlinking program very fast. Its complexity is its algorithm for attempting to merge two separate hardlink groups of the same file. Only when all the files of two hardlink groups finally merged together as a single hardlinked group, is disk space saved, so it goes to great effort to find all such files.

The primary purpose of this program is to attempt to re-link files that were moved or renamed in "rsync" backups. This program can thus make incredible disk space savings by restoring the hardlinking between duplicate files. This commonly happens if a directory is renamed, causing the hardlinkes in a later rsync backups to not be made, even though the file itself is untouched (just the directory path).

unlinkdups: Break All Hardlinks (Shell Script)
Recursively look at the given files and the given directories and break any hardlink that is found. Basically the reverse of the previous "linkdups" script, in that it will un-merge duplicate files again, while preserving any dates and permissions.

This was needed to remove the hardlinks from files that should not have been hardlinked together. Specifically files in my working home directory that are temporary backups or revisions, configuration files, or SVN copies. This allows the 'separated' files to be able to be edited independently from each other, without a 'vi' or 'cp' modifying ALL the backup copies (revisions).

mv_renum: Rename numbered files (Perl Script)
A simple perl script which will find the largest number in the given filenames, and prepend zeros to the number found in the other filenames so they list in the correct order. An option will let you specify the number of digits to make all the numbers instead.

If this script is renamed to be "mv_reseq", it can then be used to re-sequence all the numbers, so as to remove any gaps, or spread out the numbers so as to add gaps to the sequence. This can be useful to insert and re-arrange the numbered order of the files. It is a VERY handy script.

mv_perl: Perform complex file renaming (Perl Script)
Rename files based on either a given perl substitution expression, OR using one of the many pre-prepared expressions, based on the scripts own filename.

If the script is linked/copied to the filename "cp_perl" or "ln_perl", then it will copy or symbolically link files to the new filename rather than move or rename them.

Built in perl expressions have been included to rename files to: all lowercase, all uppercase, capitalise words, remove punctuation, replace spaces with underscores, and visa-versa, and many more common file renaming.

These can accessed by linking the script to appropriate "mv_*" names (see internal documentation). For example if the script is linked/copied to the command name "mv_lcase" it will rename the given file to lowercase.

This script was originally based on a common perl renaming script, the core of which was originally created by Larry Wall, the creator of perl. Many variants exist including "mmv" and under Debian Linux "rename".

merge: Rename or Copy files safely (Shell Script)
A replacement for the 'mv' and 'cp' command to use in the previous scripts which adds numbers to the filenames to prevent files overwriting and destroying other files of the same name.

Text File Filters

randomize: Randomize lines in pipeline (Perl Script)
A simple perl script that can be used as a filter. It basically will randomize all the input lines. Essentially the opposite of the "sort" command.

randomline: Extract one random line (Perl Script)
A perl script similar to the previous one, but only outputs a single randomly picked line from the input list. Sort of a 'pick any one' type filter.

This was designed so it does not need to read in the whole input list into memory, instead only holding the 'current' selection from the list that it has already read. That is it has a very small memory footprint. Of course it will not output the final single random selection until it has finished reading all the input lines.

X Windows

xwin_find: Wait for a window and print its WindowID (Shell Script)
Wait for a specified x-window client window to appear, (or timeout), and return that windows WindowID. This ID can then be used to modify the application window such as resize, move, iconize it. The script is basically a simple looped wrapper around the standard "xwininfo" command.

Currently it could use a re-write at this point in time to make better use of newer x window control tools.

jiggle_window: Window shake or bounce (Shell Script)
Jiggle (move around) a window in some specific way so as to highlight the window or some condition to the user.

By default it will cause the window specified to 'bounce' like a ball to highlight its existance. Other actions include 'shake' left and right, which is commonly used to indicate some error condition (bad password).

A xwit version and a xdotool version is available.

edit_textbuf: Edit a Web text buffer in VI (Shell Script)
Grab the text from current text buffer input field, pop up your prefered editor with that text. When Editor ends, paste the text back into the original text buffer.

This program should be linked to a key sequence such as 'Window-Control-V'

Network

ping_monitor: monitor machine network status. (Perl_Tk script)
Display a table of hosts and indicate if the hosts are currently pingable. used to set up a monitor of what machines in a lab are up and currently in use. Machines automatically power off when not in use.

Graphics

Gif trans (.c) and Man Page (.man) and Text Manual (.txt)
This is a patched version of the "giftrans" program. That fixes some reported GIF file setting numbers (bad rolls) and comment handling of the more modern "rgb.txt" files. It should be compiled with a RGBTXT define giving the location of the "rgb.txt" file, though it is not strictly necessary for its correct working.

I use this program in some of my icon library scripts to gather information about GIF files, such as the exact colormap, disposal, and delay settings from GIF animations.

Also see ImageMagick Examples, Helper Scripts, and especially the "gif2anim" script. This script originally used this program for information gathering to create a ImageMagick command that can re-build the animation from its de-composed frames. However no it uses ImageMagick itself to gather this data.

XbmBrowser v5.1b.tar.gz. (X Windows C program)
This is an interactive X bitmap and pixmap browser.

The program is a must, for exploring and viewing my icon library, and without which the library would have been an impossibility.

Shell Scripting

Percent: Generate a Percentage Bar (Shell Script)
Generate a ASCII percentage bar, that can be printed to a terminal or included in plain test emails.

Homespace: report home disk or quota left (Shell Script)
Look up disk or quota space, used and free, of the users home, and report it in a nice way using either the previous 'percentage' script, or using a 'zenity' percentage bar.

Timeout: kill long running commands (Shell Script)
A complex script that runs the given command, but will then kill it, if the command has not completed in the time specified.

This is useful to prevent network commands taking too long waiting for slow remote servers when the information is not that important. For example when getting a hostname from a network IP, or disk quota when the file system is on a remote NFS server that is down.

The script is completely 'Bourne Shell' based, and uses some very complex scripting tricks to allow it to, exit immeditatally the command does, without any 'sleep interval' pauses, or leaving behind a long running sleep command. For more details of its developemnt see my notes in "Shell Script Hints, and the section "Command Timeout".

Linux machine often have a C version, also called 'timeout', but that is not always available on non-linux machines, and that is where this program fills the gap.

Countdown: A test command for timeout scripts (Shell Script)
This is just a simple script outputing a countdown reminisent of a NASA rocket launch. It is used as a test command for testing timeout programs and scripts to see how well they work.

See my notes in "Shell Script Hints, and the section "Command Timeout".

Shell Co-Processing

shell_select.pl: select system call for shell (Perl Script)
A small simple perl script to allow access to the UNIX select() system from a shell script which is handling multiple data pipelines. This is typically required in a complex shell co-process programming technqiue.

Also see shell_select_example.sh, which is a demonstration program using "shell_select.pl" to handle both normal result output, and error output form a "bc" co-process.

For more information see my own notes on running "Co-Processes in Shell Scripts, and the section on "Multiple Output Streams".

shell_expect: simple static co-processing script (Shell Script)
A generic but simple co-processing scripting method feeding static requests after waiting for specific prompts from the process being feed the data.

Based on a similar script by Steve Parker, "Simple Expect Replacement". See my own notes on running "Co-Processes in Shell Scripts, in the section on "Timed Data Pipelines".

WWW Programs (Client)

www_ctrl: Web Browser Remote Control. (Shell Script)
Read the currently selected string, and direct the Firefox web browser to either..

When configured with hotkeys such as from a Window Manager, users can simply highlight a link, word, or other text, and press some button to find out more information. Makes the lookup of more. information from emails, web pages, manuals, or terminal output very fast and efficent.

For example I have Ctrl-F12 set to go to the selected link, Ctrl-F11 for Google search, and Shift-F11 for Wikipedia Lookup. For more details with its use with OpenBox Window manager see this CrunchBang Linux Forum Discussion

WWW Programs (Server)

User Links: Generate User Home Page List. (CGI Perl Script)
A Simple program to search the users home directories for a wide world web public directory and output a "User Home Pages" document at the time of the WWW request.

The program is designed for use with the NCSA webserver, or the Apache Web server. It may however be modified to work with other servers. Or for other needs if required.

The program does assume that the password file contains user's real names and not some sort of alias such a 'Death Stalker'. This is the only source of a users real name unless modified to use some other source particular to the machine using it.

A modified version is a Sort by Surname, assuming that the name in the password file is their real name. This trys to sort the users by their last name (which is assumed to be the last word in their password files full name).

Guestbook: Simple CGI Guestbook. (CGI Perl Script)
Another perl script which allows any user on a Web Server to have a 'Guestbook' on their home page.

The Guestbook itself must be writable by 'nobody', and called "guestbook.html", and can contain a opening comment and final address. I used this as my own guestbook for about 6 years before I discontinued it. Web users today are so much more apathetic about things like this.

A "QUERY_STRING" included in the forms ACTION call to this program contains the login name of person who's guestbook is to be updated, and an optional flag allowing a particular guestbook to be 'reversed' so that the newest entries are first. Any entry added is also mailed to that guestbook owner so that he can see new entries that were added, and make a correction if necessary.

The Form input accepts four fields, containing the users 'real name', 'email address', 'home page' and a single line 'comment'. The last two are optional and can be left blank. From this a guestbook entry is created and inserted. For an example form look at my own guestbook input form.

The program is designed for use with the NCSA Http Server, but may be modified to work with other servers. Or for other needs if required.

Counter: generate counter image. (CGI Perl Script)
Counter Images Archive. (Gziped Tar file)
A very simple counter script written in perl. This script features

This is a very simple perl program which extracts the counter location from the "Extra URL path information", when the script is called. The counter image output by the program is handled by an external image filter package such a ImageMagick or PbmPlus filters, under the script s control. That is the script itself does not handle the images!

Due to this use of external image filters, more complex counters can be created using almost any set of `digit images' and can be used to create

The counter is also easily expanded to handle, and may have other capabilities added to it in the future For more information have a look in my WWW Laboratory at the information about Anthony's Counter.

test-cgi: Check input arguments to CGI. (CGI Perl Script)
This is a simple script I use for testing HTML forms and links to see what the current server and client would supply to a CGI script. All it does is output the following information... Basically all the information available to a cgi script when run.

This script is used in "Sorcery of Form Input" in my Castle's WWW Laboratory.

Talk: WWW Adventure Interaction. (CGI Perl Script)
This is the program I use to handle the "talk to person" type forms I use in my Castle Adventure Home Page. But I make this available for others to use.

A very simple program which is given a "QUERY_STRING", used to locate a talk data file, and a simple form 'message'. The message is parsed so as to remove extra spaces, punctuation, and converted to lowercase. It is then compared against the contents of the talk data file and when a match is found the user's client is jumped to the URL associated with that response.

If the users response or message is not known they are jumped to a default URL also given in the data file. Also the unknown response is (optionally) mailed to a particular person (me) so as to allow unknown responses to be added later if appropriate, or to find abusers of the adventure game.

For example this program is used to communicate with Castle's resident Dragon, which can be seen at Balcony over the Dragon's Lair deep in the Castle Dungeons.

Blackboard. (CGI Perl Script)
I created this program to use in the classroom of the castle. It provides a way for passing WWW users to leave a message for the next user. I have also linked the program to `figlet' to allow a small phrase to be 'graffiti' onto the blackboard.

The script takes great pains to ensure that a HTML program will parse the output correctly. It does this by replacing the special characters such as "<" with the html sequence "&lt;" so that the characters will be displayed properly.

This program is used to implement the blackboard in the Castle's Classroom.

Mail Filters

MH Send Filter (Shell Script)
This script pretends to be the MH send program and collect the out going mail. Which is passed to a mail filter of your choice, before being passed to the real MH mail system `send' command. This allows you to append signatures, add mail faces or just edit outgoing mail in some fashion (PGP encryption?).

The script is installed by modifing your personal ".mh_profile" to use this command for the mh send, as well as the real mh send command to use, and the mail filter this script is to call.

Unix Sendmail Filter (Shell Script)
This script complements the above MH send filter but replaced the normal system sendmail command.

To use this filter you specify this program in your personal ".mailrc". Unfortunately the filter called by this script must be specified inside the script itself. The same output mail filter can however be used for both MH and BSD mail systems.

Outgoing Mail Filter (Shell Script)
This script is my personal outgoing mail filter, which the above scripts call. This script actually adds signatures, mail face, and other mail header modifications to my outgoing mail, automatically.

ANSI Graphics Scripts

graphics (Shell Script)
graphics2 (Shell Script)
graphics_colors (Shell Script)
graphics_utf (Shell Script)
Various scripts I wrote a long time ago (1990's before X windows became common) to check on the ANSI graphics capabilities of my current terminal.

The exact results vary greatly depending on the terminal program (especially for colors and attributes) and on the font you are using. It seems that many of the special ANSI graphic character modes are no longer functional with the more modren UTF fonts, but then they have other methods of use the vast UTF characters now available.

Created: 3 May 1995
Updated: 21 September 2011
Author: Anthony Thyssen, <A.Thyssen@griffith.edu.au>