读书笔记--101个shell脚本--05

The Code

#!/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