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Please explain read in a while loop

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Top Forums Shell Programming and Scripting Please explain read in a while loop
# 1  
Old 01-11-2006
Please explain read in a while loop
I have a script which tries to read input from a user for every value read from a file. The input file is

Code:
#> more testfile
TEST1 | D200 | 12345601 | | ABC company | m
TEST2 | D201 | 12345602 | | ABC company | m

The script test.sh is as follows

Code:
while read line
do
read test?"Enter a Value:"
done < testfile

however when executed, shell never responds to a the read command.

Code:
#>test.sh
#>

Is there a special read option that I have to use when using read within a while loop? Any help is greatly appreciated. Thanks

Jerardfjay Smilie
# 2  
Old 01-11-2006
Code:
count=`wc -l file1 | tr -s " " | cut -d" " -f 2`
echo $count

while test $count -gt 0
do
    echo "Enter input :"
    read input
    echo $input
    ((count=count-1))
done

Last edited by bhargav; 01-11-2006 at 04:48 PM..
# 3  
Old 01-11-2006
Quote:
Originally Posted by bhargav
Code:
count=`wc -l file1 | tr -s " " | cut -d" " -f 2`
echo $count

while test $count -gt 0
do
    echo "Enter input :"
    read input
    echo $input
    ((count=count-1))
done

Bhargav,

I need to read input from user for every line that I read from the testfile. How would I accomplish that. Your example does not involve the loop reading from a file as well as reading user input within the loop of reading from a file. I use the $line variable within the loop to extract data that I require for other purposes.

Code:
while read line
do
    var1=$(echo "${line}" | awk -F "|" '{print $2}' | sed -e 's/^ *//g;s/ *$//g')
    read input?"Enter value :"      <<<---- This read does not work
    echo $input
#    do some processing with $var1 and $input and continue 
done < testfile

Any thoughts?
Jerardfjay
Last edited by jerardfjay; 01-11-2006 at 05:27 PM.. Reason: clarification of reply
# 4  
Old 01-11-2006
Code:
 while read line
do
read test?"Enter a Value:"
done < testfile


In the above code, in the first line, it says read line.. it reads the first line from the testfile and puts it into the variable called line, again when you say read test, it actually reads the second line from testfile and puts it into the variable test.. it won't take the input from the keyboard because you have given the input as testfile by specifying the "<".

use this code

#!/usr/bin/ksh

IFS="
"

for line in $(< testfile)
do
echo $line
echo "Enter value :"
read a
done
Last edited by mahendramahendr; 01-11-2006 at 05:44 PM..
# 5  
Old 01-11-2006
Or do this:
Code:
while read line
do
read test?"Enter a Value:"  < /dev/tty
done < testfile

# 6  
Old 01-12-2006
Thanks
Thanks mahendramahendr and Perderabo. Both of your code works. However I prefer perderabo's snippet since I dont have to mess around with IFS. Thanks for your valuable input.

Regards
Jerardfjay
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