Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
f1
# Still an error message.
# However...
f1 ()
{
echo "Calling function \"f2\" from within function \"f1\"."
f2
}
f2 ()
{
echo "Function \"f2\"."
}
f1 # Function "f2" is not actually called until this point,
#+ although it is referenced before its definition.
# This is permissable.
# Thanks, S.C.
It is even possible to nest a function within another function, although this is not very useful.
f1 ()
{
}
f2 () # nested
{
echo "Function \"f2\", inside \"f1\"."
}
f2 # Gives an error message.
# Even a preceding "declare −f f2" wouldn't help.
echo
f1 # Does nothing, since calling "f1" does not automatically call "f2".
f2 # Now, it's all right to call "f2",
#+ since its definition has been made visible by calling "f1".
# Thanks, S.C.
Function declarations can appear in unlikely places, even where a command would otherwise go.
ls −l | foo() { echo "foo"; } # Permissable, but useless.
if [ "$USER" = bozo ]
then
bozo_greet () # Function definition embedded in an if/then construct.
{
echo "Hello, Bozo."
}
fi
bozo_greet
# Works only for Bozo, and other users get an error.
Chapter 23. Functions 275