Linux/Unix Shell Scripting - Alguien me corrige este script?

#!/bin/bash

while read line ; do

echo "$line"

if [ "$line" -gt "0" ] ;then echo "$line" >> /home/alum1/f2.txt

elif [ "$line" -lt "0" ] ;then echo "$line" >> /home/alum1/f3.txt

if [ "$line" -eq "0" ] ;then echo "$line" >> /home/alum1/f2.txt

done < /home/alum1/f1.txt

#!/bin/bash

while read line ; do

echo "$line"

if [ "$line" -gt "0" ] ;then echo "$line" >> /home/alum1/f2.txt

elif [ "$line" -lt "0" ] ;then echo "$line" >> /home/alum1/f3.txt

fi

if [ "$line" -eq "0" ] ;then echo "$line" >> /home/alum1/f2.txt

fi

done < /home/alum1/f1.txt

while read line

do

	if [ "$line" -lt "0" ]

	then

		echo "$line" >> /home/alum1/f3.txt

	else

		echo "$line" >> /home/alum1/f2.txt

	fi

done < /home/alum1/f1.txt