tagls is a tool that matches file names using boolean expressions made of tags and regular expressions. It handles searching in file lists with word boundaries for "tags", stemming and synonym expansion for both tags and regular expressions, and boolean expressions over lists of tags or regular expressions. It can match against either the file name or the file's content. The output can be unsorted, sorted by name, or sorted by relevance.
waitcond is a script to specify a combination of events using boolean expressions over various events. It can periodically grep in files, wait for the (dis)appearance of files or processes, wait for certain CPU/net/disk idle values, or wait for an idle tty. waitcond is meant to be combined with some notification tool or system.
SQL Tagger reads the tags of audio files from a directory, loads them into a temporary SQLite database, accepts SQL queries to modify this database, then saves any changes back to the audio files. It's useful for performing complex updates that would be difficult or tedious with conventional taggers. It's a complement to conventional taggers, not a replacement.
phpdocr will download, prettify, and output PHP documentation for the function or class that is supplied on the command-line, much like perldoc does for Perl and ri does for Ruby. Unless you explicitly tell it not to, phpdocr will also cache the documentation locally for fast retrieval in the future.
fnf is a script that provides a list of a Twitter user's friends and followers. If you provide a username (and optional proxy), fnf will generate two files: USERNAME.followers and USERNAME.friends, consisting of a list of Twitter screen names and real names separated by " :: ". This data is easily used in scripts or imported to spreadsheets.