[Bash] convert cpu No. into a bitmask

#!/bin/bash # convert cpu No. into a bitmask for taskset # To avoid this conversion, you can simply use "-c" option # @ http://scriptdemo.blogspot.com # check whether it is a valid number getValid() {    if [[ $1 =~ "^[0-9]+$" ]]; then       if [ $1 -lt 1 ] || [ $1 -gt ${numCPUs} ]; then          echo "FAIL"       else          echo $1;       fi    else       echo "cpu No. must be between 1-${numCPUs}"       echo "FAIL"    fi } numCPUs=`cat /proc/cpuinfo | grep "model name" | wc -l` if [ $# -eq 0 ]; then    echo "Usage: cpumask.sh CPU_No"    exit elif [ $# -eq 1 ]; then    if [[ $1 =~ "^[0-9]+$" ]]; then       cpuNo=`getValid $1`    else       echo "cpu No. must be between 1-${numCPUS}"       exit    fi    if [[ ${cpuNo} =~ "FAIL" ]]; then       echo "invalid cpu No: $1"       echo " valid cpu No: 1-${numCPUs}"       exit    else       cpuMask=`echo "ibase=10; obase=16; 2^(${cpuNo}-1)" | bc`    fi else   cpuMask=0   eval "cpuNoInput=( `echo $* | sed 's/\ /\n/g' | sort | uniq` )"   for cputmp in ${cpuNoInput[*]}   do       cpuNo=`getValid ${cputmp}`       if [[ ${cpuNo} =~ "FAIL" ]]; then          echo "invalid cpu No: ${cputmp}"          echo " valid cpu No: 1-${numCPUs}"          exit       fi       cpuMasktmp=`echo "ibase=10; obase=16; 2^(${cpuNo}-1)" | bc`       cpuMask=`echo "ibase=16; obase=10; ${cpuMask}+${cpuMasktmp}" | bc`   done fi cpuMaskBinary=`echo "ibase=16; obase=2; ${cpuMask}" | bc` echo " Total cpus availbale: ${numCPUs}" echo " request cpu mask(B): ${cpuMaskBinary}" echo " request cpu mask(H): ${cpuMask}" echo " taskset 0x${cpuMask} YourCommand"

To use cpu: #1 #2 #3 #7 #8