Shell Programming and Scripting

# cat /root/nums
1
2
3

# cat /root/read.sh
#!/bin/bash

var="NONE"
cat /root/nums | while read entry
do
        var=`echo $entry`
        echo $var
done

echo $var

# sh  /root/read.sh
1
2
3
NONE

# sh  /root/read.sh
1
2
3
3

while read entry
do
        var=`echo $entry`
        echo $var
done < /root/nums

while read entry
do
        var=`echo $entry`
        echo $var
done < <(grep something somefile)

#!/bin/bash

var="NONE"
#cat nums | while read entry
while read entry
do
        export var=$entry
        echo $var
done<nums

echo $var

$!/bin/bash
var=$( [ -s /root/nums ] && tail -n 1 /root/nums || echo NONE )
printf '%s\n' "$var"

#!/bin/bash
var="NONE"
while read -r entry
do
        var="$entry"
done</root/nums
printf '%s\n' "$var"