#!/bin/bash
func1 ()
{
echo This is a function.
}
declare -f # Lists the function above.
echo
declare -i var1 # var1 is an integer.
var1=2367
echo "var1 declared as $var1"
var1=var1+1 # Integer declaration eliminates the need for 'let'.
echo "var1 incremented by 1 is $var1."
# Attempt to change variable declared as integer.
echo "Attempting to change var1 to floating point value 2367.1."
var1=2367.1 # Results in error message, with no change to variable.
echo "var1 is still $var1"
echo
declare -r var2=13.36 # 'declare' permits setting a variable property
#+ and simultaneously assigning it a value.
echo "var2 declared as $var2" # Attempt to change readonly variable.
var2=13.37 # Generates error message, and exit from script.
echo "var2 is still $var2" # This line will not execute.
exit 0 # Script will not exit here.
结果
[root@localhost shell]# ./ex20.sh
func1 ()
{
echo This is a function.
}
var1 declared as 2367
var1 incremented by 1 is 2368.
Attempting to change var1 to floating point value 2367.1.
./ex20.sh: line 19: 2367.1: syntax error: invalid arithmetic operator (error token is ".1")
var1 is still 2368
var2 declared as 13.36
./ex20.sh: line 27: var2: readonly variable
var2 is still 13.36