Advanced Bash−Scripting Guide

# grep PATTERN /etc/passwd | awk −F":" '{ print $5 }'
# or
# awk −F: '/PATTERN/ {print $5}'
# or
# awk −F: '($1 == "username") { print $5 }' # real name from username
# However, it might not be as instructive.
exit 0
Advanced Bash−Scripting Guide
There is an alternative, and perhaps less confusing method of redirecting a function's stdin. This
involves redirecting the stdin to an embedded bracketed code block within the function.
# Instead of:
Function ()
{
...
} < file
# Try this:
Function ()
{
{
...
} < file
}
# Similarly,
Function () # This works.
{
{
echo $*
} | tr a b
}
Function () # This doesn't work.
{
echo $*
} | tr a b # A nested code block is mandatory here.
# Thanks, S.C.
23.2. Local Variables
What makes a variable "local"?
local variables
A variable declared as local is one that is visible only within the block of code in which it appears. It
has local "scope". In a function, a local variable has meaning only within that function block.
Example 23−8. Local variable visibility
#!/bin/bash
func ()
Chapter 23. Functions 283