How to check for Input Redirection in my script?

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03-30-2010

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One way which works whether the data is presented on a pipeline, an inward redirect, or interactive.

Code:

#!/bin/ksh
#
# If nothing is using channel zero we are interactive
if [ -t 0 ]
then
        while true
        do
                echo "Enter data line: "; read line
                if [ "${line}""X" = "X" ]
                then
                        exit
                fi
                echo "${line}"
        done
fi
#
# Data is piped to this script
(
while read line
do
        echo "${line}"
done
) <&0

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