Advanced Bash−Scripting Guide

{
local loc_var=23 # Declared local.
echo
echo "\"loc_var\" in function = $loc_var"
global_var=999
# Not declared local.
echo "\"global_var\" in function = $global_var"
}
func
# Now, see if local 'a' exists outside function.
echo
echo "\"loc_var\" outside function = $loc_var"
# "loc_var" outside function =
# Nope, $loc_var not visible globally.
echo "\"global_var\" outside function = $global_var"
# "global_var" outside function = 999
# $global_var is visible globally.
echo
exit 0
Advanced Bash−Scripting Guide
Before a function is called, all variables declared within the function are invisible outside the
body of the function, not just those explicitly declared as local.
#!/bin/bash
func ()
{
global_var=37
# Visible only within the function block
#+ before the function has been called.
} # END OF FUNCTION
echo "global_var = $global_var" # global_var =
# Function "func" has not yet been called,
#+ so $global_var is not visible here.
func
echo "global_var = $global_var" # global_var = 37
# Has been set by function call.
23.2.1. Local variables make recursion possible.
Local variables permit recursion, [53] but this practice generally involves much computational overhead and
is definitely not recommended in a shell script. [54]
Example 23−9. Recursion, using a local variable
#!/bin/bash
# factorial
# −−−−−−−−−
# Does bash permit recursion?
# Well, yes, but...
Chapter 23. Functions 284