(linux/bash) 쉘 스크립트 function 함수 관련

#!/bin/bash
#
round2() {
	printf "%.${2}f" "${1}"
}

PI=3.14159

round2 ${PI} 0
echo
round_PI=$(round2 $PI 3)
echo $round_PI

floor() {
	printf "%.0f" ${1}
}

ceil() {
	echo ""
}

round() {
	echo ""
}
echo "----------"
num=3.6
floor $num

echo "---------------"
function test {
  echo "test will return 12"
  return 12
 }

 test
 echo "return value of test: $?"

function test() {
   echo "hello"
 }

 echo "$(test) world!"

 num1=1
 num2=2

 function test {
   num1=3
   local num2=4

   echo "num1 in test: $num1"
   echo "num2 in test: $num2"
 }

 echo "num1: $num1"
 echo "num2: $num2"

 test

 echo "num1: $num1"
 echo "num2: $num2"

 function add_all() {
   local result=0

   for num in $@
     do
       let result+=num
     done

   echo $result
 }

result=`(add_all 1 2 3 4 5)`
echo "result: $result"

my_function() {
  echo "some result"
  return 55
}

my_function
echo $?

my_function() {
  func_result="some result"
 }

my_function
echo $func_result

my_function() {
  local func_result="iiisome result"
  echo $func_result
}

echo $(my_function)
#echo $func_resul

echo "----------------"

simple_function() {
  for ((i=0;i<5;++i)) do
    echo " $i ";
  done
  echo
}

simple_function

function simple_inputs() {
  echo "This is the first argument [$1]"
  echo "This is the second arguement [$2]"
  echo "Calling function with $# arguments"
}

simple_inputs one 'two three'

sum=0
function simple_outputs() {
  let sum=$1+$2
}

simple_outputs 1 2
echo "Sum is $sum"

function simple_outputs() {
  let sum=$1+$2
  echo $sum
}

sum=$(simple_outputs 1 2)
echo "Sum is $sum"

function ref_outputs() {
  declare -n sum_ref=$3
  sum_ref=$(($1+$2))
}

ref_outputs 11 2 sum
echo "sum is $sum"

var="baeldung"
function var_scope() {
  local var="lorem"
  echo "variable inside function var_scope: [$var]"
}

var_scope
echo "Variable outside function var_scope: [$var]"

var="baeldung"

function var_scope2() {
  echo "Variable inside function var_scope2: [$var]"
}
function var_scope() {
  local var="lorem"
  echo "Variable inside function var_scope: [$var]"
  var_scope2
}

var_scope

sum=0
#function simple_subshell() {
#  sum=$3
#  let sum=$1+$2
#}

sum=0
function simple_subshell() {
  declare -n sum_ref=$3
  let sum_ref=$1+$2
}

simple_subshell 4 5 sum
echo "Sum is $sum"

simple_subshell 3 4 sum
echo "Sum is $sum"

# 외부 파일에서 읽어와서 처리하기
filename="infile"
outfile="outfile"
function redirection_in() {
  line=0
  while read input;
  do
    len=`echo $input | wc -w`
    #echo "input=$input"
    #echo "len=$len"
    for (( i=0; i<len; i++))
    do
      echo -n ${input[$i]}
    done
    echo  
    let line++
  done
  echo "I read $line lines."
} < $filename

redirection_in

function redirection_out() {
  declare -a output=("baeldung" "lorem" "ipsum")
  for element in ${output[@]}
  do
    echo $element
  done
 } > $outfile

redirection_out


function redirection_in_ps() {
   read
   while read -a input;
   do
     echo "${input[2]} ${input[8]}"
   done
} < <(ls -ll /)

redirection_in_ps

echo "=========="
function redirection_out_ps() {
  declare -a output=("baeldung" "lorem" "ipsum" "caracg")
  for element in "${output[@]}"
  do
    echo "$element"
  done
} > >(grep "g")

redirection_out_ps


echo "----------"

function fibo() {
  num=$1
  if [ $num -eq 0 ] || [ $num -eq 1 ]; then
    echo $num
  else
    first=`fibo $((num-1))`
    second=`fibo $((num-2))`
    echo $(( $first + $second ))
  fi
}

#FUNCNEST=10
echo `fibo 5`
echo `fibo 7`
echo `fibo 6`
echo `fibo 12`

function read_and_verify {
  read -p "Please enter value for '$1': " tmp1
  read -p "Please repeat the value to verify: " tmp2
  if [ $tmp1 != $tmp2 ]; then
    echo "Values unmatched. Please try again."; return 2
  else
    declare -n ref="$1" # $1을 참조변수로 선언
    ref=$tmp   # $1에 tmp1 값을 넣음.
  fi
}

number="1234"

read_and_verify number
echo $number

#declare var
#declare -i int
# var="1+1"
# int="1+1"
# echo $var
# echo $int