Tag: bash

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Associative Arrays in Bash v4

One of the new features in Bash v4 are the associative arrays using strings as index instead numbers
here a small example of use

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#!/bin/bash
 
declare -A myArray #declare array
myArray[cat]=gato #attach a value into index cat
myArray[dog]=can #attach a value into index dog
 
creature="fish" #declare a variable
 
myArray[$creature]=peixe #attach a value into index fish
 
#get all array values
for key in "${!myArray[@]}"
 do
 echo "index value=$key content value= ${myArray[$key]}"
 done
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Boolean and numerical values equivalence in bash

One of the problems using bash is the numeric equivalence of boolean values

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#!/bin/sh
 function zero()
 {
 return 0
 }
 
function one()
 {
 return 1
 }
 
#main section
 if zero ;
 then
 echo "0 is true"
 fi
 if one ;
 then
 echo "1 is true"
 fi

and the output is:
0 is true