Bash Script Awk Condition

Question

i have a problem with this code.. i can't figure out what i have to write as condition to cut my file with awk.

i=0    
while [ $i -lt 10 ]; #da 1 a 9, Ap1..Ap9
    do

      case $i in
        1) RX="54:75:D0:3F:1E:F0";;
        2) RX="54:75:D0:3F:4D:00";;
        3) RX="54:75:D0:3F:51:50";;
        4) RX="54:75:D0:3F:53:60";;
        5) RX="54:75:D0:3F:56:10";;
        6) RX="54:75:D0:3F:56:E0";;
        7) RX="54:75:D0:3F:5A:B0";;
        8) RX="54:75:D0:3F:5F:90";;
        9) RX="D0:D0:FD:68:BC:70";;
        *) echo "Numero invalido!";;
      esac
      echo "RX = $RX" #check 
      awk -F, '$2 =="$RX" { print $0 }' File1 > File2[$i] #this is the line!
  i=$(( $i + 1 ))
  done

the command echo prints correctly but when i use the same "$RX" as condition in AWK it doesn't work (it prints a blank page). my File1 :

1417164082794,54:75:D0:3F:53:60,54:75:D0:3F:1E:F0,-75,2400,6 1417164082794,54:75:D0:3F:56:10,54:75:D0:3F:1E:F0,-93,2400,4 1417164082794,54:75:D0:3F:56:E0,54:75:D0:3F:1E:F0,-89,2400,4 1417164082794,54:75:D0:3F:5A:B0,54:75:D0:3F:1E:F0,-80,2400,4 1417164082794,54:75:D0:3F:53:60,54:75:D0:3F:1E:F0,-89,5000,2

could you tell me the right expression "awk -F ..."

thank you very much!

@anishane no, never do that. See cfajohnson.com/shell/cus-faq-2.html#Q24 for the right ways to do it. — Ed Morton
– Ed Morton, Commented Apr 1, 2015 at 15:24

a5hk · Accepted Answer · 2015-04-01 11:26:59Z

3

To pass variables from shell to awk use -v:

awk -F, -v R="$RX" '$2 ==R { print $0 }' File1 > File2[$i]

answered Apr 1, 2015 at 11:26

a5hk

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1 Comment

Ed Morton Over a year ago

and get rid of the { print $0 } as that's the default behavior so it's useless to specify it explicitly.

Ed Morton · Accepted Answer · 2015-04-01 15:47:04Z

@Ricky - any time you write a loop in shell just to manipulate text you have the wrong approach. It's just not what the shell was created to do - it's what awk was created to do and the shell was created to invoke commands like awk.

Just use a single awk command and instead of reading File 10 times and switching on variables for every line of the file, just do it all once, something like this:

BEGIN {
    split(file2s,f2s)
    split("54:75:D0:3F:1E:F0\
           54:75:D0:3F:4D:00\
           54:75:D0:3F:51:50\
           54:75:D0:3F:53:60\
           54:75:D0:3F:56:10\
           54:75:D0:3F:56:E0\
           54:75:D0:3F:5A:B0\
           54:75:D0:3F:5F:90\
           D0:D0:FD:68:BC:70", rxs)
    for (i in rxs) {
        rx2file2s[rxs[i]] = f2s[i]
    }
}
{
    if ($2 in rx2file2s) {
        print > rx2file2s[$2]
    }
    else {
        print NR, $2, "Numero invalido!" | "cat>&2"
    }
}

which you'd then invoke as awk -v file2s="${File2[@]}" -f script.awk File1

I say "something like" because you didn't provide any sample input (File1 contents) or expected output (File2* values and contents) so I couldn't test it but it will be very close to what you need if not exactly right.

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