Please explain read in a while loop

jerardfjay · #1 (**permalink**) 01-11-2006

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

bhargav · #2 (**permalink**) 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

jerardfjay · #3 (**permalink**) 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

mahendramahendr · #4 (**permalink**) 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

Perderabo · #5 (**permalink**) 01-11-2006

Or do this:

Code:

while read line
do
read test?"Enter a Value:"  < /dev/tty
done < testfile

jerardfjay · #6 (**permalink**) 01-12-2006

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

More UNIX and Linux Forum Topics You Might Find Helpful
Thread	Thread Starter	Forum	Replies	Last Post
ls while read loop - internal read picking up wrong input	dkieran	Shell Programming and Scripting	2	05-14-2007 03:02 PM
While read loop and rsh	104234	UNIX for Advanced & Expert Users	1	01-15-2006 11:53 AM
input inside while read loop	jhansrod	Shell Programming and Scripting	3	08-13-2005 10:46 AM
Nested while read line loop	Rakker	Shell Programming and Scripting	7	06-24-2005 07:42 AM
read inside a while loop	dta4316	UNIX for Dummies Questions & Answers	3	05-21-2005 10:53 AM

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes	Rate This Thread
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode	Rate This Thread:


	Powered by