Using variables created sequentially in a loop while still inside of the loop [bash] Post: 302327901

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Top Forums Shell Programming and Scripting Using variables created sequentially in a loop while still inside of the loop [bash] Post 302327901 by DeCoTwc on Monday 22nd of June 2009 11:54:58 PM

06-23-2009

Registered User

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

DeCoTwc

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LEARN ABOUT MOJAVE

seq

SEQ(1)							    BSD General Commands Manual 						    SEQ(1)

NAME

     seq -- print sequences of numbers

SYNOPSIS

     seq [-w] [-f format] [-s string] [-t string] [first [incr]] last

DESCRIPTION

     The seq utility prints a sequence of numbers, one per line (default), from first (default 1), to near last as possible, in increments of incr
     (default 1).  When first is larger than last the default incr is -1.

     All numbers are interpreted as floating point.

     Normally integer values are printed as decimal integers.

     The seq utility accepts the following options:

     -f format	   Use a printf(3) style format to print each number.  Only the E, e, f, G, g, and % conversion characters are valid, along with
		   any optional flags and an optional numeric minimum field width or precision.  The format can contain character escape sequences
		   in backslash notation as defined in ANSI X3.159-1989 (``ANSI C89'').  The default is %g.

     -s string	   Use string to separate numbers.  The string can contain character escape sequences in backslash notation as defined in ANSI
		   X3.159-1989 (``ANSI C89'').	The default is 
.

     -t string	   Use string to terminate sequence of numbers.  The string can contain character escape sequences in backslash notation as
		   defined in ANSI X3.159-1989 (``ANSI C89'').	This option is useful when the default separator does not contain a 
.

     -w 	   Equalize the widths of all numbers by padding with zeros as necessary.  This option has no effect with the -f option.  If any
		   sequence numbers will be printed in exponential notation, the default conversion is changed to %e.

     The seq utility exits 0 on success and non-zero if an error occurs.

EXAMPLES

	   # seq 1 3
	   1
	   2
	   3

	   # seq 3 1
	   3
	   2
	   1

	   # seq -w 0 .05 .1
	   0.00
	   0.05
	   0.10

SEE ALSO

     jot(1), printf(1), printf(3)

HISTORY

     The seq command first appeared in Plan 9 from Bell Labs.  A seq command appeared in NetBSD 3.0, and ported to FreeBSD 9.0.  This command was
     based on the command of the same name in Plan 9 from Bell Labs and the GNU core utilities.  The GNU seq command first appeared in the 1.13
     shell utilities release.

BUGS

     The -w option does not handle the transition from pure floating point to exponent representation very well.  The seq command is not bug for
     bug compatible with the Plan 9 from Bell Labs or GNU versions of seq.

BSD
								 February 19, 2010							       BSD

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LEARN ABOUT MOJAVE

seq