"Integer expression expected" bash if statements - bash

Question

I'm trying to extract the xy coordinates of some earthquake occurrences along with their magnitudes from a file "seismic_c_am.txt", and plot them as circles of various sizes and colours based on the magnitude. Here is what I have so far:
25 i=`awk '{ FS = "|" ; print $11}' seismic_c_am.txt`
26
27 if [ "$i" -gt 7 ] ; then
28 awk 'NR%25==0 { FS = "|" ; print $4, $3}' seismic_c_am.txt | psxy $rgn $proj -Sc0.25c -Gred -O -K >> $psfile ;
29 fi
30
31 if [ "$i" -gt 5 ] && [ "$i" -le 7 ] ; then
32 awk 'NR%25==0 { FS = "|" ; print $4, $3}' seismic_c_am.txt | psxy $rgn $proj -Sc0.2c -Gorange -O -K >> $psfile ;
33 fi
34
35 if [ "$i" -le 5 ] ; then
36 awk 'NR%25==0 { FS = "|" ; print $4, $3}' seismic_c_am.txt | psxy $rgn $proj -Sc0.1c -Gyellow -O -K >> $psfile ;
37 fi
This script seems to just print all the magnitudes ($11) into the terminal, and the last line reads:
.
.
3.6
4.0
1.7
3.6 : integer expression expected
But I don't know which line this is referring to! Possibly line 27, 31 or 35? (see above)

Answer 1

Bash doesn't do floating point arithmetic, only integer arithmetic.
Since you're comparing with integers, you can make awk print the integer part.
i=`awk '{ FS = "|" ; printf "%d", $11}' seismic_c_am.txt`
If you want to know which line is causing these errors, add the command set -x to your script to turn on tracing mode: bash will print each script line before executing it. If you only want to trace part of the script, you can turn off tracing with set +x.
Since you're repeating the same snippet many times, you may want to restructure your script a bit.
i=`awk '{ FS = "|" ; printf "%d", $11}' seismic_c_am.txt`
if [ $i -ge 7 ]; then
sc_value=0.25 color=red
elif [ $i -ge 5 ]; then
sc_value=0.2 color=orange
else
sc_value=0.1 color=yellow
fi
awk 'NR%25==0 { FS = "|" ; print $4, $3}' seismic_c_am.txt |
psxy $rgn $proj -Sc${sc_value}c -G$color -O -K >> $psfile