74 lines
1.9 KiB
Bash
Executable file
74 lines
1.9 KiB
Bash
Executable file
# Originally
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#
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# From: bsh20858@news.fhda.edu (Brian S Hiles)
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# Newsgroups: comp.unix.shell
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# Subject: Re: getting random numbers
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# Date: 23 Jan 1997 23:27:30 GMT
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# Message-ID: <5c8s52$eif@tiptoe.fhda.edu>
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# @(#) krand Produces a random number within integer limits
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# "krand" Korn shell script generates a random number in a
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# specified range with an optionally specified ``seed'' value.
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# Author: Peter Turnbull, May 1993
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# Modified by: Becca Thomas, January 1994
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# changed the optional third argument to a -s option, converted to
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# bash v2 syntax -- chet@po.cwru.edu
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PROGNAME=${0##*/}
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USAGE="usage: $PROGNAME [-s seed] lower-limit upper-limit"
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Seed=$$ # Initialize random-number seed value with PID
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usage()
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{
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echo ${PROGNAME}: "$USAGE" >&2
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}
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errexit()
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{
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echo ${PROGNAME}: "$@" >&2
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exit 1
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}
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# Process command-line arguments:
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while getopts "s:" opt; do
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case "$opt" in
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s) Seed=$OPTARG ;;
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*) usage ; exit 2;;
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esac
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done
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shift $(($OPTIND - 1))
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case $# in
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2) Lower=$1; Upper=$2 ;;
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*) usage ; exit 2;;
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esac
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# Check that specified values are integers:
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expr "$Lower" + 0 >/dev/null 2>&1
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[ $? -eq 2 ] && { errexit "lower ($Lower) not an integer"; }
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expr "$Upper" + 0 >/dev/null 2>&1
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[ $? -eq 2 ] && { errexit "upper ($Upper) not an integer"; }
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expr "$Seed" + 0 >/dev/null 2>&1
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[ $? -eq 2 ] && { errexit "seed ($Seed) not an integer"; }
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# Check that values are in the correct range:
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if (( "$Lower" < 0 )) || [ ${#Lower} -gt 5 ]; then
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errexit "lower limit ($Lower) less than zero"
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fi
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if (( "$Upper" > 32767 )) || [ ${#Upper} -gt 5 ]; then
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errexit "upper limit ($Upper) greater than 32767"
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fi
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if (( "$Seed" < 0 )) || (( "$Seed" > 32767 )) || [ ${#Seed} -gt 5 ]; then
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errexit "seed value ($Seed) out of range (0 to 32767)"
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fi
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(( "$Upper" <= "$Lower" )) && errexit "upper limit ($Upper) <= lower limit ($Lower)"
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# Seed the random-number generator:
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RANDOM=$Seed
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# Compute value, scaled within range:
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let rand="$RANDOM % ($Upper - $Lower + 1) + $Lower"
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# Report result:
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echo $rand
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