awk --> math-operation in a array

Shell Programming and Scripting
1

Hi

main object is categorize the difference of data-values (TLUFT02B - TLUFT12B).
herefor i read out data-files which are named
acording to the timeformat yyyymmddhhmm.

WR030B      266.48 Grad      0
WR050B      271.46 Grad      0
WR120B      268.11 Grad      0
WV030B        2.51 m/s       0
WV050B        3.47 m/s       0
WV120B        4.82 m/s       0
TLUFT02B      7.82 �C       0
TLUFT12B      6.87 �C       0
NSCHLB        0.00 mm        0

i try to read out the data and write it in a new file, with ...

#!/bin/bash
a=$(date --date '1 month ago' +%m)
e=$(date +%m)
y=$(date +%Y)
home=$HOME/Desktop/Messdaten/METE
cd $home
fpat=$(ls `eval echo $y{$a,$e}*` | tail -n 1584) ## 1584 Dateien entspr. 11 Tagen
for i in $fpat
do
      if test -f "$i"
      then
         Dy=${i:2:2} Dm=${i:4:2} Dd=${i:6:2}
        UZh=${i:8:2} UZm=${i:10:2}
        res=$(awk '{A[$1]=$2}END{print A["WV120B"], A["WR120B"], A["NSCHLB"], A["TLUFT12B"], A["TLUFT02B"]}' OFS='\t' "$i")
       T120=$(awk '{B[$1]=$2}END{print B["TLUFT12B"]}' "$i")
        T20=$(awk '{C[$1]=$2}END{print C["TLUFT02B"]}' "$i")
        printf "%s/%s/%s-%s:%s\t%s\t%s\n" $Dm $Dd $Dy $UZh $UZm "$res" "$T20-$T120"
      else
        DAT=$(date +%Y%m%d)
        printf "$DAT - Datei $i nicht vorhanden" >> "$home/../Logfiles/Log_$(date +%Y%m%d).log"
    fi
done

I want the difference of the values T20 and T120 -- blue!
but in the printf-comand gave me the listed values seperatet by the minus.
Please, can someone give me a hint
thanks in advance,
IMPe

2

You are printing string find out difference here

Integer

$ a=10; b=8
$ printf "%d\n" $(echo "$a-$b" | bc)
2

Floating point

$ a=10; b=8
$ printf "%f\n" $(echo "$a-$b" | bc)
2.000000

String

$ a=10; b=8
$ printf "%s\n" "$a-$b"
10-8

print as string after calculation

$ a=10; b=8
$ printf "%s\n" $((a-b))
2
1 Like
3

Instead of "$T20-$T120" , the proper syntax would be "$(( T20 - T120 ))"
--edit--
That should be $(echo "$T20 - $T120" | bc) since it is bash , not ksh93

1 Like
4

Thank you for your immediate help - i understand the mistake! Unfortunately it is not working well. i changed ...

printf "%s/%s/%s-%s:%s\t%s\t%f\n" $Dm $Dd $Dy $UZh $UZm "$res" "$T20-$T120"

... the script printout gave me

line 17: printf: 17.10-17.02: invalid number

thanks in advance!
IMPe

5

it was supposed to be

$((T20-T120))

OR

$(echo "$T20-$T120" | bc)
1 Like
6

Thanks a lot! Sorry i've forgotten to tell, that i'm using bash. And with
$(echo "$T20 - $T120" | bc)
it's working fine.
how can i extend the echo-term. finally i want to check in which range the difference is. So is it between 0 an 1, then print A. Is it between 1 and 2 print B.
Is it possible to construct this with a case-statement?

Thanks in advance!
IMPe

7

As you are using awk anyhow, why don't you do the maths and formatting all in one single awk script? Might be clearer, cleaner and easier to maintain.

1 Like