Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
echo
echo "$count: ${Countries[@]}" # Print resultant array at end of each pass.
echo
let "count += 1"
# Increment pass count.
done
# End of outer loop
# All done.
exit 0
−−
Is it possible to nest arrays within arrays?
#!/bin/bash
# Nested array.
# Michael Zick provided this example.
AnArray=( $(ls −−inode −−ignore−backups −−almost−all \
−−directory −−full−time −−color=none −−time=status \
−−sort=time −l ${PWD} ) ) # Commands and options.
# Spaces are significant . . . and don't quote anything in the above.
SubArray=( ${AnArray[@]:11:1} ${AnArray[@]:6:5} )
# Array has two elements, each of which is in turn an array.
echo "Current directory and date of last status change:"
echo "${SubArray[@]}"
exit 0
−−
Arrays enable implementing a shell script version of the Sieve of Eratosthenes. Of course, a
resource−intensive application of this nature should really be written in a compiled language, such as C. It
runs excruciatingly slowly as a script.
Example 26−7. Complex array application: Sieve of Eratosthenes
#!/bin/bash
# sieve.sh
# Sieve of Eratosthenes
# Ancient algorithm for finding prime numbers.
# This runs a couple of orders of magnitude
# slower than the equivalent C program.
LOWER_LIMIT=1 # Starting with 1.
UPPER_LIMIT=1000 # Up to 1000.
# (You may set this higher... if you have time on your hands.)
PRIME=1
NON_PRIME=0
Chapter 26. Arrays 301