Snipplr - deepsoul

(Perl) Process quoted text differently

Mon, 18 Jun 2012 05:00:57 GMT

This Perl snippet shows how to separate quoted parts from a text in order to process quoted and unquoted parts separately. For example, you could expand variables or wildcards only in the unquoted part. Then the different processed parts are put together again. That a marker character "\x01" is used to mark the position of the quoted passages is a bit ugly, but on the other hand the single line of code putting the text together again is very elegant and shows off what Perl can do!

(Haskell) Simultaneous filter and map

Thu, 06 Oct 2011 07:53:01 GMT

The `filtermap` functional below allows to perform the standard `map` and `filter` operations in one go. The mapping function has to return a `Maybe` monad, and values of `Nothing` are filtered out.

(Perl) Short-circuited Perl grep

Mon, 11 Jul 2011 06:34:41 GMT

To check the existence of an element in a Perl array with specific properties, one tends to use `grep`. But this is inefficient because `grep` always checks each element. (Even in scalar context it returns the number of matching elements.) The following function aborts after the first find.

(C) Determine word sizes by cross-compiling only

Mon, 11 Jul 2011 06:08:22 GMT

You can find out the word sizes and endianness of a device by compiling the following program with a cross compiler and looking at the executable with the `strings` program or a hex editor. The `TESTIF` macro puts a copy of the statement to test and its truth value into a string which will be present in the exe. This helps if you do not have such a device handy, or if it is cumbersome to access (requires loading firmware etc.).

(JavaScript) Bookmarklet to page history on the Internet Archive

Thu, 18 Mar 2010 16:21:15 GMT

This bookmarklet points to the Internet Archive overview page for the current page. Insert it into your page or bookmark it [right here](javascript:location.href='http://web.archive.org/web/*/'+location.href).

(Haskell) Interval of integral points

Thu, 18 Mar 2010 16:15:42 GMT

These functions return all points (pairs or triples of coordinates) within a given rectangle or box. ``pam`` is the reverse map function which was defined [here](http://snipplr.com/view/18351/reverse-map/).

(C) Log all output to file

Thu, 18 Mar 2010 16:03:19 GMT

With the code fragment below, you can easily add output logging to a text-based program. Add the functions, open the log file and replace calls to (f)printf by (f)printflog.

(Perl) Downgrade Visual Studio project

Thu, 18 Mar 2010 15:33:24 GMT

Some (all?) Visual Studio projects can be opened with older versions without problems once their version numbers have been reduced. The following Perl script does this; it also recurses over the projects contained in a project folder (.sln) file. It saves you upgrading all your installations.

(Bash) Replace colour range

Wed, 06 Jan 2010 07:44:53 GMT

This snippet shows how to replace the colours in a monochrome image, i.e. one which only contains two colours and the range of hues between them.

(HTML) Google search form with additional keywords

Sun, 27 Dec 2009 09:26:42 GMT

The Google search URL accepts two fields, `as_oq` and `as_eq`, which give additional required or forbidden keywords for the search. This allows to create search forms which add preset keywords. In the search form below, one of the keywords test, review or evalutation is required, and none of "buy now", "special offer" and "free download" may be present.

(Bash) Retrieve administrator excuse

Sat, 21 Nov 2009 15:58:34 GMT

Jeff Ballard provides excuses in the style of the Bastard Operator From Hell via telnet. The following should be defined as an alias (such as `excuse`) for easy access:

(Bash) Thumbnail table with date/time

Sat, 14 Nov 2009 08:41:57 GMT

This script creates thumbnail images containing 25 thumbs each and display the EXIF time and date if your version of ImageMagick supports that (some do not).

(Bash) copy, but never overwrite

Sat, 14 Nov 2009 07:48:11 GMT

Useful if some files already exist at the destination and are newer or would take too long to copy again.

(Bash) Replace background colour

Sun, 01 Nov 2009 13:53:25 GMT

When you put an image in a printable document, you don't want it to have black (or coloured) background. ImageMagick allows to replace colours even when the coloured regions are non-contiguous. Arbitrary colour values can be specified with `\#123456` (the backslash is for escaping the #). If you want to replace similar colours as well, use the `-fuzz` option.

(Bash) Find newest file and its modification time

Sun, 01 Nov 2009 13:25:08 GMT

Find the most recently modified file in a directory tree and output its name and modification time. Use index 8 or 10 instead of 9 for access and inode modification time, respectively (see perlfunc manual page - function stat). This is great for deciding what directories to backup.

(Bash) Cygwin: recursive copy with ACLs

Sun, 25 Oct 2009 12:23:47 GMT

Cygwin's `cp` discards ACLs (complex windoze permissions). You have to copy them separately as follows:

(Bash) Convert bit stream to ASCII text

Wed, 30 Sep 2009 16:03:09 GMT

Useful for decoding geek humour such as [this cartoon](http://assets.comics.com/dyn/str_strip/000000000/00000000/0000000/200000/90000/5000/900/295942/295942.full.gif). Accepts input from stdin.

(Ruby) Ruby class + method documentation

Wed, 30 Sep 2009 15:50:14 GMT

The shell command which provides documentation for Ruby's classes and methods is:

(Regular Expression) Zero version numbers to clone Cygwin installation

Wed, 30 Sep 2009 15:35:28 GMT

A Cygwin installation can be cloned by copying `/etc/setup/installed.db` and zeroing all version numbers, then running the installation utility. The following `sed` script will set the version of most packages to zero. Some non-standard version numbers will not be affected and have to be zeroed by hand.

(Bash) Get / set CPU affinity (Linux)

Thu, 17 Sep 2009 15:38:09 GMT

Start jobs bound to certain CPU(s), or find the number of available CPUs.