Utilities and Programs by M. Väth

This page contains some of the programs and utilities which I have written. Some of them are about 20 years old, but others are rather new.
You may download and modify these programs for your private use. If you make an interesting modification, I ask you to mail me a copy.
You may also distribute these programs unmodified in any form you like.
If you want to use them in a commercial environment, or if you want to distribute a modified version, please contact me.

• Download page: Some .spec files for SuSE 9.2 (last update: December 6, 2004).
• Download page: Some scripts and ebuilds for Gentoo (last update: January 31, 2010).
• Download page: Magus for SuSE 9.2 (last update: January 7, 2006).
• Download page: Packages for TeX and LaTeX (last update: August 10, 2007).
• less-select-patch-436.tar.gz (last update: July 22, 2009). With this patch you can select files (or other content) interactively from a list, using the less program. A perl script making use of this feature and executing certain commands on the selected files is also provided. The patches in this file work at least with less versions 371-436. For Gentoo, there is an ebuild script in my Gentoo download page.
• pyrep.zip (last update: February 6, 2001). (Python regular expression). A python variant of the perl script plrep described below. To adapt the colors to your taste and console, edit the strings in the first few lines.
• mv_perl.zip (last update: October 25, 2008). A collection of some perl scripts:
  • plrep v2.4 (Perl regular expression). This script provides among a more user-friendly variant of the well-known grep (with perl regular expressions) a method to replace regular expression within the files. Special features include interactive replacement, recursive directory handling, colorized display (adaptable for various terminal colors since v2.1), readable output also for mixed text/binary files (conversion to printable characters, very luxury truncation of lines), and also interactive replacement/grep of expressions across multiple lines (experimental since v2.1).
    With plrep --man you get a detailed help as a manpage (new since v2.1)
    This script requires at least Perl 5 (together with some modules). If you really must use Perl 4, you can use the scripts prep and rrep below which together have almost the same functionality.
  • patchdirs v1.9. This script serves two purposes:
    1. It allows to keep directory trees in sync for computers which have no direct connection. On the one hand, it allows to (recursively) list files together with their checksums (and dates, owners, modes). On the other hand, it can use that information to reconstruct all file renamings/deletions/copies (and owner, date, mode-changes) based on the checksum information. Even circular renamings (like swappings of filenames) can be reconstructed. Of course, this script requires a checksum utility which provides a sufficiently strong checksum (by default, the perl Digest::MD5 module is used, but not mandatory: other programs are also supported).
       The new release finally supports also copies of files, changes of directory names, and stores/restores symbolic links. Since v1.3 a --follow-link option is available, too. Since v1.7 some useful options for FAT options have been added like changing to upper/lower case or adding/subtracting a time offset.
    2. This script is able to look for double files (where duplicates are recognized by equal checksums). Since checksum information can be stored, this is particularly useful if frequently new files must be compared against a given directory tree. (If you want more reliable information than only a checksum comparison, use the double perl script of this collection).
    This script requires at least Perl 5 (with some modules).
  • patchdirs-ls v1.1. This is somewhat similar to patchdirs but can only reconstruct from an "ls --recursive" output exclusively on the base of names. This is very fast and requires no checksum module/program. However, circular renamings can of course not be recognized.
    This script is still in experimental state. It requires at least Perl 5 (with elementary modules).
  • rendirs v5.2. The "very standard" ISO9660 CD-Rom format only allows names of 8+3 characters. If there are some reasons to use this format with non-packaged files, it is often convenient to create additionally a list containing the original filenames (and perhaps with a small description of the files). This script renames the files corresponding to such a list. It also allows appropriate creation/modification of symbolic links and treatment of empty "dummy" files. Perl 5 (with elementary modules) is required.
  • sshconfig v1.1. If you frequently ssh/scp/sftp/rsync to computers with a dynamic IP address, you will find this script very useful. It modifies/creates a ~/.ssh/config file for you such that you can conveniently use the "real" hostname in your commands while the correct IP address is used (enter the IP address only once for running the scipt). From a security aspect, this script is what you should use in order to associate the correct fingerprint to the host, even if its IP address changes. This helps you to detect "man in the middle" attacks.
  • prep v1.1 (Perl regular expression). Similar to the well-known grep but with perl regular expressions and possibility to recurse into subdirectories. You should also have a look at the above script plrep.
  • rrep v1.1 (Replace regular expression). As prep above, but in addition, it is possible to replace the regular expressions in the files (interactively or non-interactively). Very flexible. You should also have a look at the script plrep.
  • double v1.1. Looks for double files (the user may decide whether equal names and/or equal content count as double). Needs only O(n log(n)) comparisons in the mean. See also the patchdirs script of this collection.
  • renreg v1.2. Rename and/or number a set of files using regular expressions.
  • changecase v1.1. A very simple script which allows to change filenames to upper or lower case (including directory names, recursively). Very useful in connection with DOS partitions or archives.
  • comp v1.2. Similar to diff -r -q, but compares also attributes, time, owner, ... Also a usage like comp *.tex DIR is admissible.
  • touch.difference v1.1. Correct times of files by a daylight saving offset.
  • touchdirs v1.2. Touch directories according to their newest file.
• bzwc.tar.gz (Revision 2.3) (last update: January 10, 2010). This is a POSIX shell wrapper for wc which decompresses ".gz", ".bz2", ".lzma", or ".xz" files before sending them to wc. All options of wc can be used, and as for usual wc, it is possible to pass several files as arguments. For standard input, the name of the command (bzwc, lzwc or zwc) determines whether .bz2 .lzwc or .gz data is assumed.
• mv_emacs.zip (last update: July 6, 2006). A collection of some Emacs Lisp (.el) scripts which should run with all newer versions of Emacs or XEmacs (Lucid Emacs).
  • block.el (revision 1.1). The standard Emacs treatment of the region is rather different from that of many of the classical text editors. In many other editors a "block" can be marked explicitly which exists independent of the current cursor position and independent of the buffer. This package is an attempt to emulate this behaviour by providing such a block and making it act as if it were the region.
  • kbdmacro.el (revision 0.3). This package provides an intuitive way to define keyboard macros (during runtime) and bind them to keys. The old meaning of the keys is remembered and can be restored. It is also possible to save all recorded macros into a file.
  • verify.el (revision 0.2). This package provides the single command verify which allows to verify conveniently whether and where the buffer was actually changed since its last "save".
• archwrap.tar.gz (last update: January 10, 2010). A collection of some POSIX shell scripts which invoke various archivers like (s)tar/bzip2/zip/... in an automized manner (e.g. to invoke all archivers and keep only the smallest archive, to unpack an arbitrary archive into some subdirectory, to repack archives, to pack to remote host etc). Lots of options control the details. I have written these scripts only for myself and not in a systematic way, but although they are short and simple, they are rather useful - e.g. if you want to unpack the content of a directory full of *.tar.bz2 *.tar.gz *.zip *.arj *.tar.lzma and other files with a single command. Also less popular but very good archivers like xz, lzma, 7z, or lrz are supported.
• looptool.zip (last update: September 30, 2005). A bash script to mount/unmount/encrypt/decrypt filesystems via the loop device. Note that this script allows you to encrypt/decrypt existing devices without using additional storage data. Be aware that this makes use of an undocumented behaviour of encrypted filesystems: Therefore this script might damage your data (even if correctly used) if the undocumented behaviour of either the loop device or of the encryption routine changes. It was only tested at some occassions with twofish on SuSE 9.0 and with twofish256 on SuSE 9.2, and I received no bug reports yet. However, please use with extreme care!
  In the new release, the default values are set for SuSE 9.2 - you must use some flags if you want the previous behaviour.
• emount.tar.gz (Version 1.4) (last update: January 10, 2010). A perl script to mount/unmount (and to create/remove) dm-crypt filesystems according to your /etc/fstab. The cryptsetup program or some equivalent script is needed.
• recovery.zip (Version 1.1) (last update: July 16, 2005). A small but very useful tool if one must use less reliable media like diskettes to store/ship data: To a given file, it generates a small recovery file which can be used to restore the given file after a slight damage, e.g. after the loss of one block of information. (The maximal size of such a block which still can be restored determines of course the size of the recovery file). In contrast to other utilities, it is not necessary to convert the original file into some special format: The original file can be shipped unmodified, one just has to ship the small recovery file in addition.
• hocp.zip (last update: June 5, 2000). This is an ancient program for calculation with arbitrary precision. The archive contains a subdirectory calc_c in which there are two C libraries for calculation of elementary resp. transcendental functions with arbitrary precision. The main directory contains a Makefile which generates the program hocp. This program provides an interactive language to some of the library functions which is powerful enough to write small programs. The language is an extension to the language hoc which was described by Brian Kernighan and Rob Pike in their book Der UNIX-Werkzeugkasten. All documentation is in German.
• calc.zip (last update: June 5, 2000). A C++ library for arbitrary precision. Also very ancient. All documentation is in German.
• schach.zip (last update: June 5, 2000). A C library for chess. Extremely ancient, but I do not think I could write a much better version even today. A simple demo program is provided which solves all sort of chess problems, looking also for multiple solutions. This demo program is not convenient to use. For the screen output of the demo program some patches are necessary for UNIX. An executable for DOS (with DJGPP) is included in the archive. All documentation is in German.
• quintris.zip (last update: November 9, 2003). Everybody knows Tetris. But this little game is different. This .zip contains only a small executable for DOS and (new) for Linux (it should run on all i386 linux systems but needs an 80x25 color terminal to display well - I just crosscompiled without much porting). This game was a very short project with my brother many years ago to learn a new programming language.
• sshstart.zip (Version 2.3). (last update: January 11, 2010). A frontend for ssh-add and ssh-agent which asks you for the passphrase automatically but only the first time you run ssh and friends. The keychain script is supported if it is available (a reasonable new version of that script is required). Use sshstart -h to get a description.
• video.tar.gz (Version 3.13). (last update: January 23, 2010). A bash frontend for mplayer/mencoder and alsa to record movies from TV or to re-encode them (possibly with several passes).
• sudox.zip (Version 2.1). (last update: January 10, 2010). This script is similar to sux. It is a wrapper for sudo which can transfer X authority data (optionally generating "untrusted" permissions). In addition, some support for the screen program is provided, taking care of tty permissions. For a description, use ./sudox -? or ./sudox -h. If you had trouble with this script in earlier versions, try to add keep_env+="TRANSFER" to your /etc/sudoers file.
• firewall.zip (Version 5.5). (last update: January 24, 2010). This script sets some typical iptables commands for a dialup PC, optionally including a simple portknocking solution and router functionality. The usage is somewhat similar to SuSEfirewall2, but the approach has some essential differences. In particular, packets are usually not DROPed but REJECTed until a rate-limit is reached. It is not necessary to restart the firewall after a connection is established. The setting of the kernel variables is done with a separate script. Currently, IPv6 is not supported by the script. The port-knocking setup is only available since Version 3.0. The router functionality is only available since Version 4.0. Since Version 4.0 the script is POSIX compliant ("local" should be known).
• starter.zip (Version 1.5). (last update: January 10, 2010). This script can be used to schedule commands in a multitasking and multiuser environment. Commands started with this script will wait with the execution until all earlier commands started earlier with this script (possibly by a different user) have been executed. You can also have several of such command queues or add a command to a queue even if you start it immediately. There is also a wrapper script which may be used to queue shell-commands.

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