Error: integer expression expected

Question

I have written a script to determine the Load average on the server as follows:

#!/bin/bash loadavg=`top -b -n1 | grep -i load | awk -F, '{print$4}'| awk -F: '{print $2}'` if [ "${loadavg}" -le 1 ] then echo "OK - Load Average = ${loadavg} | Load_Average=${loadavg}" exit 0; elif [ "${loadavg}" -gt 1 ] && [ "${loadavg}" -le 2 ] then echo "WARNING - Load Average = ${loadavg} | Load_Average=${loadavg}" exit 1; elif [ "${loadavg}" -gt 2 ] then echo "CRITICAL - Load Average = ${loadavg} | Load_Average=${loadavg}" exit 2; else echo "UNKNOWN - Load Average = NaN | Load_Average=NaN" fi 

When the script is executed, it displays following error:

./loadavg.sh ./loadavg.sh: line 5: [: 0.06: integer expression expected ./loadavg.sh: line 9: [: 0.06: integer expression expected ./loadavg.sh: line 13: [: 0.06: integer expression expected UNKNOWN - Load Average = NaN | Load_Average=NaN 

Answer 1

bash (contrary to ksh93 or zsh¹) can't do floating point arithmetics. awk can though, so you can do the whole thing in awk.

Also, you don't need to use top (and wait 1 second) to get the load. The canonical way to get the load is from uptime.

uptime | awk '{load=+$(NF-2)} load > 2 {print "CRITICAL: " load; exit 2} load > 1 {print "WARNING: " load; exit 1} {print "OK: " load; exit 0} END {if (!NR) {print "UNKNOWN"; exit 3}' exit 

---

^{1 In zsh though, you need to use the (( loadavg > 2 )) instead of [ "$loadavg" -gt 2 ] syntax for comparing non-integers}

Answer 2

top -b -n1 | grep -i load | awk -F, '{print$4}'| awk -F: '{print $2}' returns nada, hence your errors.

Answer 3

Your loadavg is null, causes syntax errors by [:

$ top -b n1 | grep -i load | awk -F, '{print$4}'| awk -F: '{print $2}' <blank line here> 

You must change it to:

$ top -b n1 | grep -i load | awk -F, '{print$4}'| awk -F: '{print $1}' 0.24 

However, you should use newer test in your script, it can handle this problem:

$ [[ "" -gt 1 ]] || echo "OK" OK 

With older [:

$ [ "" -gt 1 ] || echo "OK" bash: [: : integer expression expected OK 

Updated

bash can not handle floating point numbers, so your comparison (even with new test [[..]]) will show errors.

You can use another tools to do this task, like bc, awk...

Example:

$ [[ $(echo "3 > 1" | bc -l) == 1 ]] && echo OK OK $[[ $(echo "3 < 1" | bc -l) == 1 ]] || echo Not OK Not OK 

Answer 4

First off, running top is more expensive than just grabbing "uptime".

$ uptime 16:15:38 up 6 days, 23:22, 23 users, load average: 0.99, 0.82, 0.70 

Second, as @Stéphane Chazelas mentioned, bash doesn't like floating point arithmetic.

$ [[ "0.1" -lt 1 ]] bash: [[: 0.1: syntax error: invalid arithmetic operator (error token is ".1") 

Fortunately, bash expansion can take care of that. From man bash:

 ${parameter%word} ${parameter%%word} Remove matching suffix pattern. The word is expanded to produce a pattern just as in pathname expansion. If the pattern matches a trailing portion of the expanded value of parameter, then the result of the expansion is the expanded value of parameter with the shortest matching pattern (the ``%'' case) or the longest matching pattern (the ``%%'' case) deleted. If parameter is @ or *, the pattern removal operation is applied to each positional parameter in turn, and the expansion is the resultant list. If parameter is an array variable sub- scripted with @ or *, the pattern removal operation is applied to each member of the array in turn, and the expansion is the resultant list. 

So it becomes pretty easy to strip out the decimal portions with "%.*"

$ la=`uptime | sed 's/.*average: \([0-9\.]*\).*/\1/'` $ if [ ${la%.*} -lt 1 ]; then echo "OK - Load average is $la"; fi OK - Load average is 0.42