shell脚本nicenumber实现代码

given a number, shows it in comma-separated form.expects dd and td to be instantiated. instantiates nicenum. or, if a second arg is specified, the output is echoed to stdout.

废话不多说，首先是

#!/bin/sh
# nicenumber -- given a number, shows it in comma-separated form.
# expects dd and td to be instantiated. instantiates nicenum
# or, if a second arg is specified, the output is echoed to stdout.

nicenumber()
{
 # note that we assume that '.' is the decimal separator in
 # the input value to this script. the decimal separator in the output value is
 # '.' unless specified by the user with the -d flag

 integer=$(echo $1 | cut -d. -f1)       # left of the decimal
 decimal=$(echo $1 | cut -d. -f2)       # right of the decimal

 if [ $decimal != $1 ]; then
  # there's a fractional part, so let's include it.
  result="${dd:="."}$decimal"
 fi

 thousands=$integer

 while [ $thousands -gt 999 ]; do
  remainder=$(($thousands % 1000))  # three least significant digits

  while [ ${#remainder} -lt 3 ] ; do # force leading zeros as needed
   remainder="0$remainder"
  done

  thousands=$(($thousands / 1000))  # to left of remainder, if any
  result="${td:=","}${remainder}${result}"  # builds right to left
 done

 nicenum="${thousands}${result}"
 if [ ! -z $2 ] ; then
  echo $nicenum
 fi
}

dd="." # decimal point delimiter, to separate integer and fractional values
td="," # thousands delimiter, to separate every three digits

while getopts "d:t:" opt; do
 case $opt in
  d ) dd="$optarg"  ;;
  t ) td="$optarg"  ;;
 esac
done
shift $(($optind - 1))

if [ $# -eq 0 ] ; then
 echo "usage: $(basename $0) [-d c] [-t c] numeric value"
 echo " -d specifies the decimal point delimiter (default '.')"
 echo " -t specifies the thousands delimiter (default ',')"
 exit 0
fi

nicenumber $1 1     # second arg forces nicenumber to 'echo' output

exit 0

这脚本我们以后分析，现在先mark下。