Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
padding=000
# Use at most 3 zeroes to pad.
soun=$prefix$suffix$padding
MAXLEN=4
soundex=${soun:0:$MAXLEN}
# Pad with zeroes.
# Truncate to maximum of 4 chars.
echo "Soundex = $soundex"
echo
# The soundex code is a method of indexing and classifying names
#+ by grouping together the ones that sound alike.
# The soundex code for a given name is the first letter of the name,
#+ followed by a calculated three−number code.
# Similar sounding names should have almost the same soundex codes.
# Examples:
# Smith and Smythe both have a "S−530" soundex.
# Harrison = H−625
# Hargison = H−622
# Harriman = H−655
# This works out fairly well in practice, but there are numerous anomalies.
#
#
# The U.S. Census and certain other governmental agencies use soundex,
# as do genealogical researchers.
#
# For more information,
#+ see the "National Archives and Records Administration home page",
#+ http://www.nara.gov/genealogy/soundex/soundex.html
# Exercise:
# −−−−−−−−
# Simplify the "Exception Patch" section of this script.
exit 0
Example A−11. "Game of Life"
#!/bin/bash
# life.sh: "Life in the Slow Lane"
# ##################################################################### #
# This is the Bash script version of John Conway's "Game of Life". #
# "Life" is a simple implementation of cellular automata. #
# −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− #
# On a rectangular grid, let each "cell" be either "living" or "dead". #
# Designate a living cell with a dot, and a dead one with a blank space.#
# Begin with an arbitrarily drawn dot−and−blank grid, #
#+ and let this be the starting generation, "generation 0". #
# Determine each successive generation by the following rules: #
# 1) Each cell has 8 neighbors, the adjoining cells #
#+ left, right, top, bottom, and the 4 diagonals. #
# 123 #
Appendix A. Contributed Scripts 379