Process memory monitoring script for Zabbix

proc_mem.sh

#!/usr/bin/env bash
#
# proc_mem.sh:
# Process memory monitoring script for Zabbix
#
# $1: process name
# $2: effective user name
# $3: mode(sum/max/min/avg)
# $4: args pattern
#

# Get parameters from args(set default if no param).
[ -z "$1" ] && COMM='.*' || COMM="$1"
[ -z "$2" ] && EUSER='.*' || EUSER="$2"
[ -z "$3" ] && MODE='sum' || MODE="$3"
[ -z "$4" ] && ARGS_PATTERN='.*' || ARGS_PATTERN="$4"

# Get process list.
PLIST=$( ps -eo rss,comm,euser,args --no-headers )

# Calculate min, max, avg or sum by specified parameter.
case "${MODE}" in
  "min")
    echo "${PLIST}" \
      | awk -v comm="^${COMM}$" -v euser="^${EUSER}$" -v args_pattern="${ARGS_PATTERN}" \
        'BEGIN {MIN=0;CNT=0}{
           if (($2 ~ comm) && ($3 ~ euser)){
             args="";
             for(i=4;i<=NF;i++){args=args""$i};
             if (args ~ args_pattern) {
               if (CNT == 0) { MIN=$1;CNT+=1 } else if ( MIN > $1 ) { MIN=$1 }
             }
           }
         } END {print MIN}'
  ;;
  "max")
    echo "${PLIST}" \
      | awk -v comm="^${COMM}$" -v euser="^${EUSER}$" -v args_pattern="${ARGS_PATTERN}" \
        'BEGIN {MAX=0}{
           if (($2 ~ comm) && ($3 ~ euser)){
             args="";
             for(i=4;i<=NF;i++){args=args""$i};
             if (args ~ args_pattern) {
               if (MAX < $1) { MAX=$1 }
             }
           }
         } END {print MAX}'
  ;;
  "avg")
    echo "${PLIST}" \
      | awk -v comm="^${COMM}$" -v euser="^${EUSER}$" -v args_pattern="${ARGS_PATTERN}" \
        'BEGIN {SUM=0;CNT=0}{
           if (($2 ~ comm) && ($3 ~ euser)){
             args="";
             for(i=4;i<=NF;i++){args=args""$i};
             if (args ~ args_pattern) { SUM+=$1;CNT+=1 }
           }
         } END {printf("%d\n", SUM/CNT)}'
  ;;
  "sum")
    echo "${PLIST}" \
      | awk -v comm="^${COMM}$" -v euser="^${EUSER}$" -v args_pattern="${ARGS_PATTERN}" \
        'BEGIN {SUM=0}{
           if (($2 ~ comm) && ($3 ~ euser)){
             args="";
             for(i=4;i<=NF;i++){args=args""$i};
             if (args ~ args_pattern) { SUM+=$1 }
           }
         } END {print SUM}'
  ;;
  *)
    exit 1
  ;;
esac

exit 0