Using variables created sequentially in a loop while still inside of the loop [bash]


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# 1  
Using variables created sequentially in a loop while still inside of the loop [bash]

I'm trying to understand if it's possible to create a set of variables that are numbered based on another variable (using eval) in a loop, and then call on it before the loop ends.

As an example I've written a script called question (The fist command is to show what is the contents of the variable $tab)
Code:
    (23:32:12\[deco@S.Man)
    [~/bin]$ listQpsk 40|grep -w [1-4]
    40 SMANHUBAQPSK1          1    1344      1195        88
    40 SMANHUBAQPSK1          2    1668      1470        88
    40 SMANHUBAQPSK1          3    1881      1539        81
    40 SMANHUBAQPSK1          4    1686      1409        83


    (23:18:42\[deco@S.Man)
    [~/bin]$ cat question
    #!/usr/bin/bash
    tab=`listQpsk 40|grep -w [1-4]`
    seq=1
    num=4
    until [[ $seq -gt $num ]];do
    eval count$seq=`echo "$tab"|grep -w $seq|awk '{print $5}'`
    seq=$(($seq+1))
    done
    echo $count1
    echo $count2
    echo $count3
    echo $count4

When I run this I get
Code:
    (23:32:23\[deco@S.Man)
    [~/bin]$ ./question 
    1195
    1471
    1538
    1409

Which is exactly what I would expect, but is there a way to move the echo commands inside of the until loop so that part of the loop is echoing the value of the variable that was just created. Something like:

Code:
    until [[ $seq -gt $num ]];do
    eval count$seq=`echo "$tab"|grep -w $seq|awk '{print $5}'`
    seq=$(($seq+1))
    echo "$count$seq"
    done

# 2  
can you put set -x in the second line of your file "question" and paste the output here...
# 3  
Quote:
Originally Posted by rakeshawasthi
can you put set -x in the second line of your file "question" and paste the output here...
This is the output with set -x command added:

Code:
(16:48:46\[deco@S.Man)
[~/bin]$ ./question 
++ listQpsk 40
++ grep -w '[1-4]'
+ tab=' 40 SMANHUBAQPSK1          1    1342      1194        88
 40 SMANHUBAQPSK1          2    1668      1464        87
 40 SMANHUBAQPSK1          3    1883      1535        81
 40 SMANHUBAQPSK1          4    1685      1399        83'
+ seq=1
+ num=4
+ [[ 1 -gt 4 ]]
++ echo ' 40 SMANHUBAQPSK1          1    1342      1194        88
 40 SMANHUBAQPSK1          2    1668      1464        87
 40 SMANHUBAQPSK1          3    1883      1535        81
 40 SMANHUBAQPSK1          4    1685      1399        83'
++ grep -w 1
++ awk '{print $5}'
+ eval count1=1194
++ count1=1194
+ seq=2
+ [[ 2 -gt 4 ]]
++ echo ' 40 SMANHUBAQPSK1          1    1342      1194        88
 40 SMANHUBAQPSK1          2    1668      1464        87
 40 SMANHUBAQPSK1          3    1883      1535        81
 40 SMANHUBAQPSK1          4    1685      1399        83'
++ grep -w 2
++ awk '{print $5}'
+ eval count2=1464
++ count2=1464
+ seq=3
+ [[ 3 -gt 4 ]]
++ echo ' 40 SMANHUBAQPSK1          1    1342      1194        88
 40 SMANHUBAQPSK1          2    1668      1464        87
 40 SMANHUBAQPSK1          3    1883      1535        81
 40 SMANHUBAQPSK1          4    1685      1399        83'
++ grep -w 3
++ awk '{print $5}'
+ eval count3=1535
++ count3=1535
+ seq=4
+ [[ 4 -gt 4 ]]
++ echo ' 40 SMANHUBAQPSK1          1    1342      1194        88
 40 SMANHUBAQPSK1          2    1668      1464        87
 40 SMANHUBAQPSK1          3    1883      1535        81
 40 SMANHUBAQPSK1          4    1685      1399        83'
++ grep -w 4
++ awk '{print $5}'
+ eval count4=1399
++ count4=1399
+ seq=5
+ [[ 5 -gt 4 ]]
+ echo 1194
1194
+ echo 1464
1464
+ echo 1535
1535
+ echo 1399
1399

However I was able to find a working solution to my problem:

Code:
(16:48:50\[deco@S.Man)
[~/bin]$ cat orig.question 
#!/usr/bin/bash
tab=`listQpsk 40|grep -w [1-4]`
seq=1
num=4
until [[ $seq -gt $num ]];do
var="count$seq"
eval var=`echo "$tab"|grep -w $seq|awk '{print $5}'`
echo $var
seq=$(($seq+1))
done

(16:50:12\[deco@S.Man)
[~/bin]$ ./orig.question 
1194
1464
1534
1399

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