Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
. data−file # Load a data file.
# Same effect as "source data−file", but more portable.
# The file "data−file" must be present in current working directory,
#+ since it is referred to by its 'basename'.
# Now, reference some data from that file.
echo "variable1 (from data−file) = $variable1"
echo "variable3 (from data−file) = $variable3"
let "sum = $variable2 + $variable4"
echo "Sum of variable2 + variable4 (from data−file) = $sum"
echo "message1 (from data−file) is \"$message1\""
# Note: escaped quotes
print_message This is the message−print function in the data−file.
exit 0
File data−file for Example 11−18, above. Must be present in same directory.
# This is a data file loaded by a script.
# Files of this type may contain variables, functions, etc.
# It may be loaded with a 'source' or '.' command by a shell script.
# Let's initialize some variables.
variable1=22
variable2=474
variable3=5
variable4=97
message1="Hello, how are you?"
message2="Enough for now. Goodbye."
print_message ()
{
# Echoes any message passed to it.
if [ −z "$1" ]
then
return 1
# Error, if argument missing.
fi
echo
until [ −z "$1" ]
do
# Step through arguments passed to function.
echo −n "$1"
# Echo args one at a time, suppressing line feeds.
echo −n " "
# Insert spaces between words.
shift
# Next one.
done
echo
Chapter 11. Internal Commands and Builtins 140