Shell Arithmetic

반응형

Creating Inter Variables

number=123.45  // type : local string
integer counter=12 // type : local integer
typeset -i total=32767
exort total // type : export integer
integer minimum=-2147483648 // type : local integer

Base10 and Others

typeset -i int_num=10    //value string: 10
typeset -i2 bin_num=10  //value string: 2#1010
typeset -i8 oct_num=10  //value string: 8#12
typeset -i16 hex_num=10  //value string: 16#a

Working with Arithmetic

let x=4+5 // ((x=4+5))
let "x= 4 + 5" // (( x = 4 + 5 ))
print $((x=4+5))  --> 9
print $x ---> 9

Binary Operators 

<<   shift bits left   (( 8 << 1 ))  --> 16  // 1000   10000
>>   shift bits right (( 8 >> 1 )) -->  4  //   1000   100
&     bitwise AND  (( a & b )) ---> // 1000 & 0100   = 0000
|       bitwise OR    (( a | b ))  ----> // 1000 & 0110  = 1110  
^     bitwise exclusive OR  (( a^b )) ----> // 1000 & 1110 = 0110

Working with Numeric Data

awk    : UNIX command/program language
bc      : Desktop calculator  
expr   : Expression command with functions
$(#string) : Length of string variable contents
PPID : Integer number of parents process
RANDOM : Random integer
SECONDS : Elapsed secons

반응형

• 카카오스토리
• 트위터
• 페이스북

'IoT 과정' 카테고리의 다른 글

Shell Patterns  (0)	2017.07.07
Branches and Logic Testing  (0)	2017.07.06
Shell Arithmetic  (0)	2017.07.06
Designing Program Output  (0)	2017.07.06
User Input  (0)	2017.07.05
Variable  (0)	2017.07.05