Various (LGPLv2) scripts that I've created (ordered by popularity).
These have only been tested on linux, but most should work on any UNIX.
For development history see github.com/pixelb/scripts.

Name	Description	Type
l	An enhanced and more portable `ls -l`	shell
ps_mem.py	list processes by memory usage	python
crudini	handle ini files from shell	python
errno	show all errnos or meaning of specified errno	shell
findrepo	find a string in a repository working copy	shell
newest	list newest (modified) files in tree	shell
timeout	run a command with a timeout	shell
truncate	truncate a file to the specified size	shell
split_to	run a command with chunks of input	shell
sw	simple command line stopwatch script	shell
gcccpuopt	get optimum gcc options for your CPU	shell
whatrequires	list reverse dependencies on rpm or deb distros	python
fix	edit a file while not changing the modification time	shell
ansi2html.sh	convert ANSI colours to HTML	shell
inpy	enhanced python interactive introspection	python
dutop	better du	python
add	sum a column of numbers. See also funcpy	shell
find_mm_yyyy	list files last modified in mm yyyy	shell
disk_grep	find a string in a disk device	shell
idiff	colour diff output for easy review	shell
urldiff	compare URLs directly	shell
svndiff	review svn repo changes with graphical diff viewer	shell
xchat_warn	popup message when referenced directly in xchat	python
ximkeys	show keys available in X to generate a character	python
lomount.sh	loopback mount partitions within a disk image file	shell
tcpdump_not_me	Allow running tcpdump on remote system over ssh	shell
ccodes	list country codes in locale database	shell
ansi_colours.sh	display all ANSI colours	shell
funcpy	functional command line toolkit	python
bc	invoke bc with some useful functions predefined	bc
getpw	Shows how to securely prompt for a password	shell
command_prompt_here	Open a terminal in current/selected directory in nautilus	python
xfullmag	Start xmag full screen with specified magnification	shell
sysinfo	show a quick summary of system hardware	shell
human.py	convert numbers for human consumption	python
dosfiles	find text files with any CRLF line terminators	shell
day	display the date for {this,next,last} {mon,tue,...}	shell
datedir	set date of directory based on contents	shell
lsdate	print date (of file) as ls would	shell
lsmode	print file permissions in octal (like chmod accepts)	shell
bashfeed	generate feed for newest files in website (example)	shell
threadsafe	search C/C++ files for functions that are not threadsafe	shell
moz	open specified file in mozilla	shell
sematree	lock files with semaphore interface	shell
download	Download list of URLs from file with history	shell
quote	reformat misquoted mail	shell
gen_timeline	generate page for newest files in website (example)	shell
lowercase	efficiently change any uppercase names in tree	shell
rmws	remove redundant whitespace from files	shell
conv	simple wrapper around units	shell
self_modify.sh	e.g. script to show self modifying	shell
7seg	e.g. script to show self referencing	shell