Shell Programming and Scripting

awk "BEGIN {if($PERCENT<$WARNING)

                {print \"OK\" ; exit 0}

        else if(($PERCENT>=$WARNING) && ($PERCENT<$CRITICAL))

                {print \"WARNING\" ; exit 1}

        else if($PERCENT>=$CRITICAL)

                {print \"CRITICAL\" ; exit 2}

}"

awk "BEGIN {if($PERCENT<$WARNING)

                {print \"OK\" ; exit 0}

        else if(($PERCENT>=$WARNING) && ($PERCENT<$CRITICAL))

                {print \"WARNING\" ; exit 1}

        else if($PERCENT>=$CRITICAL)

                {print \"CRITICAL\" ; exit 2}
        else
                {print \"UNKNOWN\" ; exit 3}
}"

#!/bin/ksh
# shellfunc() -- Verify range
#       This function performs the same checks as the awk script written
#       in-line in this script below.  It prints the same messages, and returns
#       the same values as the awk script.  As with the awk script it gets the
#       values of $PERCENT, $WARNING, and $CRITICAL from the environment.
shellfunc() {
        if [ "$PERCENT" == "" ] || [ $(expr "$PERCENT" : ".*[^0-9]") -gt 0 ]
        then    echo "NULL OR NON-NUMERIC PERCENT"
                return 3
        fi
        if [ "$PERCENT" -lt "$WARNING" ]
        then    echo OK
                return 0
        fi
        if [ "$PERCENT" -ge "$WARNING" ] && [ "$PERCENT" -lt "$CRITICAL" ]
        then    echo WARNING
                return 1
        fi
        if [ "$PERCENT" -ge "$CRITICAL" ]
        then    echo CRITICAL
                return 2
        fi
        echo UNKNOWN
        return 3
}

# Main program follows:
#
#Usage: tester [percent [warning [critical]]]
#   This utility calls a modified version of the awk script given in the thread
#   titled "modify awk", a more traditional version of a similar awk script,
#   and a shell function that behaves similarly.  If no operands are given to
#   this script, PERCENT defaults to "40", WARNING defaults to "50", and
#   CRITICAL defaults to "90".  If warning, or warning and critical are
#   supplied, they override the default values for WARNING or WARNING and
#   CRITICAL (but they won't be overridden by empty strings.  There is no
#   checking for bad values for WARNING and CRITICAL (except that if an empty
#   string is provided for either of these values, the default will still be
#   used.
#
#   Invoking this program as follows will test various featres:
#       tester  (use default values, should print OK with exit codes 0)
#       tester 60 (sets PERCENT=60; should print WARNING with exit codes 1)
#       tester 98 (sets PERCENT=98; should print CRITICAL with exit codes 2)
#       tester 90x (should print NULL OR NON-NUMERIC PERCENT with exit codes 4)
#       tester "" (should print NULL OR NON-NUMERIC PERCENT with exit codes 4)
PERCENT=${1-40}
WARNING=${2:-50}
CRITICAL=${3:-90}
echo "Values in use for this execution:"
printf "PERCENT=\"%s\" WARNING=\"%s\" CRITICAL=\"%s\"\n\n" \
        "$PERCENT" "$WARNING" "$CRITICAL"

# Evaluate parameters using modified awk with shell parameter parsing:
echo "Calling modified awk script:"
awk "BEGIN {
        if((\"$PERCENT\" == \"\") || (\"$PERCENT\" ~ /[^0-9]/))
                {print \"NULL OR NON-NUMERIC PERCENT\"; exit 4}
        if(\"$PERCENT\" < \"$WARNING\") {print \"OK\"; exit 0}
        if((\"$PERCENT\" >= \"$WARNING\") && (\"$PERCENT\" < \"$CRITICAL\"))
                {print \"WARNING\"; exit 1}
        if(\"$PERCENT\" <= \"$CRITICAL\") {print \"CRITICAL\"; exit 2}
        print "UNKNOWN"
        exit 3
}"
printf "Modified mixed awk exit code: %d\n\n" $?

# Evaluate parameters using traditional awk script:
echo "Calling traditional awk script:"
awk -v pct="$PERCENT" -v warn="$WARNING" -v crit="$CRITICAL" 'BEGIN {
        if((pct=="") || (pct~/[^0-9]/))
                {print "NULL OR NON-NUMERIC PERCENT"; exit 4}
        if(pct<warn) {print "OK"; exit 0}
        if((pct >= warn) && (pct < crit))
                {print "WARNING"; exit 1}
        if(pct <= crit) {print "CRITICAL"; exit 2}
        printf "UNKNOWN"
        exit 3
}'
printf "Traditional awk exit code: %d\n\n" $?

# Evaluate parameters using shellfunc():
echo "Calling shellfunc:"
shellfunc
printf "shellfunc() return code: %d\n" $?

chmod +x tester

tester # Use default value for $PERCENT (40)
tester 75 # Set $PERCENT to 75 (generate Warning message)
tester 95 # Set $PERCENT to 95 (generate Critical message)
tester "" # Set $PERCENT to an empty string (generate NULL string error)
tester 12x # Set $PERCENT to 12x (generate non-numeric error)