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Issue in using read keyword twice

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# 1  
Old 12-21-2014
Issue in using read keyword twice
Hi,

I have a situation where i need to read line by line from a text pad and with each line , i need to take inputs from command line and do some process.
Using below code i am not able to use 'read' keyword twice.

Can any one please help
Code:
cat > t.txt
a
d
c
 
> cat > t.ksh
while read line
do
echo "press oprion"
read kind
echo "kind=$kind
echo "line=$line
done<t.txt

> sh t.ksh
press oprion
kind=d
echo line=a
press oprion
kind=
echo line=c

# 2  
Old 12-21-2014
Ravindra,

Your script:
Quote:
Originally Posted by Ravindra Swan
Code:
while read line
do
echo "press oprion"
read kind
echo "kind=$kind"
echo "line=$line"
done<t.txt

is working as written, once the missing quotes were added:
Code:
$ ksh -x t.ksh 
+ 0< t.txt
+ read line
+ echo 'press oprion'
press oprion
+ read kind
+ echo kind=d
kind=d
+ echo line=a
line=a
+ read line
+ echo 'press oprion'
press oprion
+ read kind
+ echo kind=
kind=
+ echo line=c
line=c
+ read line

The first read assigned "a" to line, the second read assigned "d" to kind. The loops repeats and assigned "c" to line and "" to kind. Maybe this would make more sense if the input file contained:
Code:
Line 1  a
Line 2  d
Line 3  c
Line 4

And the resulting output would be:
Code:
press oprion
kind=Line 2  d
line=Line 1  a
press oprion
kind=Line 4
line=Line 3  c

Is this the desired behavior?
# 3  
Old 12-21-2014
Hi derekludwig,

Thanks for reply,

My expectation is something else.

Alternate display of input from command editor and each line from text pad.
If 1,2,3 are the 3 inputs supplied, then
O/P:
Code:
kind=1
line=a
kind=2
line=d
kind=3
line=c

Last edited by Scrutinizer; 12-21-2014 at 04:57 PM.. Reason: CODE TAGS
# 4  
Old 12-21-2014
If I understand correctly, you want to read from the terminal every other time. You can do that with input redirection. Try:
Code:
exec 3<&0

while read line
        do      echo "press oprion"
                read kind <&3
                echo "kind=$kind"
                echo "line=$line"
        done < t.txt

This duplicates file descriptor 3 from stdin (terminal) fd 0. The second read uses this fd to get its input from. In the while block, stdin is redirected from your text file. Result:
Code:
press oprion
1
kind=1
line=a
press oprion
2
kind=2
line=d
press oprion
3
kind=3
line=c

This User Gave Thanks to RudiC For This Post:
Ravindra Swan
# 5  
Old 12-22-2014
Or use the extra descriptor for the while-loop's input
Code:
while read line <&3
do echo "press oprion"
read kind
echo "kind=$kind"
echo "line=$line"
done 3< t.txt

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