Shell Programming and Scripting

$ echo ${mask#2#} | awk '{for(i=1;i<=NF;i++)if($i)print i-1}' FS=
0
13
24
30

$ echo ${mask#2#} | awk '{for(i=NF;i>=1;i--)if($i)print NF-i}' FS=
0
6
17
30

$ P=( echo ${mask#2#} | awk '{for(i=NF;i>=1;i--)if($i)print NF-i}' FS= )
$ echo ${P[0]}
0
$ echo ${P[1]}
6
$ echo ${P[2]}
17
$ echo ${P[3]}
30

$ echo $SHELL
/bin/ksh
$ a=$(($a^1)) && echo $a
0
$ a=$(($a^1)) && echo $a
1
$ a=$(($a^1)) && echo $a
0
$ a=$(($a^1)) && echo $a
1
$ a=$((~$a)) && echo $a
-2
$ a=$((~$a)) && echo $a
1
$ a=$((~$a)) && echo $a
-2
$ a=$((~$a)) && echo $a
1

$ cat tst
b_d(){ echo "obase=10;ibase=2;$1"|bc ; }
d_b(){ echo "obase=2;ibase=10;$1"|bc ; }

show_bit(){
a=$1
i=0
while [ $i -lt 32 ]
do
    let i+=1
     b=${a%?}
    c=${a#$b}

    if ( return $(($c^1)) ) ; then
        echo "bit$i=$c"
         eval bit$i=$c
    fi

    d=$(b_d "$a")
    t=$(("$d">>1))
    a=$(d_b "$t")
done
}

echo "Enter binary 32 bit number"
read num
show_bit $num
$ ksh tst
Enter binary 32 bit number
1000000000000100000000001000001
bit1=1
bit7=1
bit18=1
bit31=1
$

#!/bin/ksh93

show_bit() {
   integer -i2 a=2#$1
   integer -i2 mask=2#00000000000000000000000000000001

   for (( i=0; i < 32; i++, mask=$(( mask << 1)) ))
   do
       (( $mask & $a )) &&  echo "bit$((i+1))=1"
   done
}

read num?"Enter binary 32 bit number: "
show_bit $num

$ ./tst
Enter binary 32 bit number: 01000000000000100000000001000001
bit1=1
bit7=1
bit18=1
bit31=1
$

#!/bin/ksh93

read num?"Enter binary 32 bit number: "

integer -i2 a=2#$num
integer -i2 mask=2#00000000000000000000000000000001

typeset -ui barray=(0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0)

for (( i=0; i < 32; i++, mask=$(( mask << 1)) ))
do
   nameref var=barray[$i]
   (( $mask & $a )) &&  var=1
done

# test the array values
if (( ${barray[0]} ))
then
   echo "barray[0] is 1"
else
   echo "barray[0] is 0"
fi

if (( ${barray[1]} ))
then
   echo "barray[1] is 1"
else
   echo "barray[1] is 0"
fi