Shell Programming and Scripting

 
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#!/bin/sh
# ${1-3} is the first parameter and, if blank, defaults to 3.
head -n "${1-3}" < data | awk -v OFS="," -v FS="\n" -v RS="" '{$1=$1} 1' OFS=','

awk -v MAX="${1-3}" '{ V=V","$1 }; NR==MAX { print substr(V,2); exit }' datafile

max=$1
if [ ! ${max} -ge 1 ]
then
        echo "Invalid parameter"
        exit
fi
#
counter1=0
counter2=0
#
while true
do
        counter1=$(( $counter1 + 1 ))
        found=$(grep -xl ^${counter1} filename.txt) ; reply=$?
        if [ ! $reply -eq 0 ]
        then
                echo ${counter1}
                counter2=$(( $counter2 + 1 ))
                if [ ${counter2} -ge ${max} ]
                then
                        break
                fi
        fi
done

./getlower 5
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