shell

notes ${} 和 $[] $[expression] can calculate easily. ${expression} can tell us the value of a element in array. eg val1=23 val2=24 echo $val1+$val2 echo $[$val1+$val2] #it is equal to `echo $(( $val1+$val2 )` [edemon@CentOS workspace]$ ./incalc.sh 23+24 47 assign values to array. array=(`echo {1..10}`) echo ${array[0]}” “${array[9]} [edemon@CentOS workspace]$ Read more…