Definitions and parameters of the function call
Function is a specific function completion code fragment, defined function codes may be used in a modular shell, to facilitate call, the function must be defined before they can be used.
First, define the function
method one:
Function name() {
Function code function to be implemented
}
Method Two:
function function name {
Function code function to be implemented
}
Second, the call parameters
Variable function name
Function name variable value reassignments
Function name position variable $ 1 $ 2 $ 3 .....
The following are some examples of a function parameter passing
The transfer function of the location variable
! # / bin / bash
position ######## transfer function parameters
if [$ # -ne 3]; then # If the script then the parameter is not equal three, then print script usage and exit
echo " Usage:: `the basename $ 0` PARl PAR2 PAR3"
Exit
Fi
Fun () {
echo "$ [$ 1 * $ 2 * $ 3]"
# where $ 1 $ 2 $ 3 is the location parameter function
}
Result = `Fun $ 1 $ 2 $ 3`
# and here $ 1 $ 2 $ 3 script is acceptable position parameter and location parameter function fun script is transmitted to a receiving function
echo "$ result"
Numeric array variable in the function call
#################
# define the script array, which has a value 1-5, then arry defines a function, the role of the received value of num external parameters, and each multiply the value with the sum value
num = (1 2 3 4 5 ) # define an array NUM
sum 1 = sum defined initial value # 1
# defined function array
ARRY () {
for I in "$ @" # "$ @" $ * for all parameters also represent all parameters, no need to add ""
do
the let $ SUM = * i by multiplying the value read #sum $ i, and then assigned to their
DONE
}
ARRY $ {NUM [@]} # execute the function array, reads the value of $ num.
echo $ SUM
#! / bin / the bash # script above and the action of the same script, the script is executed with the numerical parameters, loop for all numbers, multiplied by one to sum2 sum2 =. 1 for J * in $ do the let sum2 * $ J = DONE echo $ sum2
Examples The following examples of how to get the definition of the variable parameter and re-assigned to the variable function
local variable names in order not to conflict with other variables, only take effect in the function, does not affect the overall situation
#! / bin / the bash
##############
# reassigned to receive variables
# pass parameters to the function, and recalculates the assignment
############## ##
NUM = (2. 3. 1) assigned array # NUM
#-defined function array
array () {
local newNum = ($ *) # local variables defined function newNum
local local variables defined function I # I
for ((I = 0; I <$ #; i ++)) # $ # $ for all parameters received Similarly * this line is the starting value of $ i 0, as an index to the following new index value <$ #
do
Product [$ i] = $ [$ {newnum [$ i] } * 5] # newNum traverse the array each time a value multiplied by five, re-assigned to new new
DONE
}
array $ {NUM [@]} # call the function array
echo $ {Product [@] } # output value of $ num array
Small extension, function return values
! # / bin / the bash
###
function return value ## funtion return
############
Fun () {
Read -p "Enter Number:" NUM
the let $ SUM = 2 * NUM
# ? return $ value
return $ [2 * $ NUM]
}
Fun
#shell return value can not exceed 255, no matter what numbers you enter, the value of the above operations are returned within 255
echo "fun return value:? $ "