read or search the item in a file sequentially by position using unix shell script? - UNIX for Dummies Questions & Answers

lok · #1 (**permalink**) 07-06-2006

Is it we can read or search the item in a file sequentially by the position using unix shell script..??

The position i means is: for example..
inside the xxx file, it contain with:
----------------------------------------------------------------------
1200120136420 1210324120 12145123
1200120136420 1210324120 22178210
----------------------------------------------------------------------
position:
12345678901234567890123 4

Then i wanna grep or search for value in position 24 = 0.
like that.. position is count space by space or character or alphanumeric length..

vino · #2 (**permalink**) 07-07-2006

What is the significance of

Code:

position:
12345678901234567890123 4

Try this.

Code:

[/tmp]$ cat in
1200120136420 1210324120 12145123
1200120136420 1210324120 22178210
[/tmp]$ cat try.ksh
#! /bin/ksh

typeset -L24 left
typeset -R1 right

while read line 
do
        left=$line
        right=$left
        echo $right
done < in
[/tmp]$ ./try.ksh
0
0
[/tmp]$

jim mcnamara · #3 (**permalink**) 07-07-2006

Code:

awk 'substr($0,24,1)=="0"  '  filename

lok · #4 (**permalink**) 07-11-2006

Quote:

Originally Posted by jim mcnamara

Code:

awk 'substr($0,24,1)=="0"  '  filename

How if i wan to replace the 0 with any other variable??

I had try this :
#
item=10023
awk 'substr($0,24,1)=="$item" ' filename
#

but it cannot work. the system will take the $item as a string directly.

lok · #5 (**permalink**) 07-12-2006

Thanks vino.
One more question need ur help.

I write two while loop.
Can i know how to exit the second loop and go back to first loop. What is the exit status code??
i've tried 0 1 2 3 4, but it can't works.

vino · #6 (**permalink**) 07-12-2006

Quote:

Originally Posted by lok

Thanks vino.
One more question need ur help.

I write two while loop.
Can i know how to exit the second loop and go back to first loop. What is the exit status code??
i've tried 0 1 2 3 4, but it can't works.

Are you talking about nested while loops ?

Code:

while read file1line
do
  while read file2line
  do
    echo "$file1line $file2line"
    break 1
  done < file2
done < file1

jim mcnamara · #7 (**permalink**) 07-12-2006

Code:

#!/bin/ksh
myvariable="A"
awk -v var=$myvariable 'substr($0,24,1)==var  '  filename

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