Sample System Monitor Shell Script - Using Options

#!/bin/bash
# sys_monitor2.sh
# Usage: sys_monitor2.sh [-u|-d|-f (D/M)| -c number | -m number]
# Sample system monitor script using options
# Tested under Fedora 9

Invalidoptions()
{
  echo "Usage: `basename $0` [OPTIONS]"
  echo "OPTIONS:"
  echo -e "\t -d      for display today's date"
  echo -e "\t -u      for Logged in users list"
  echo -e "\t -f ARG  for Disk and Memory Statistics"
  echo -e "\t        (ARG=D for disk statistics; ARG=M for memory statistics)"
  echo -e "\t -c ARG  for Top CPU consuming process"
  echo -e "\t         (ARG=10 means top 10 process)"
  echo -e "\t -m ARG  for Top Memory consuming process"
  echo -e "\t         (ARG=10 means top 10 process)"
  echo -e "\t Note: Only one option at a time and -f,-c and -m require argument"
  exit 1
}

Isnumber()
{
  if [ $1 -eq $1 2> /dev/null ]
     then
     :
  else
     echo -e "You supplied bad argument, \"$1\" is not a number"
     Invalidoptions
  fi
}

if [ $# -lt 1 -o $# -gt 2 ]
then
  Invalidoptions
fi

if [ $# -eq 1 -a "$1" != "-d" -a "$1" != "-u" -a "$1" != "-f" -a "$1" != "-c" ]
then
  Invalidoptions
fi

if [ $# -eq 2 ] && [ "$1" != "-f" -a "$1" != "-c" -a "$1" != "-m" ]
then
  Invalidoptions
fi

choice=
top="head -$2"
while getopts udf:c:m: choice
do
case $choice in
  d) echo -e " Today's Date: \c"
     date +"  %d-%h-%Y       Time:  %T";;
  u) echo -e "\tCurrently Logged In Users"
     who;;
  f)
    if [ "$OPTARG" = "D" ]
    then
        echo -e "\t\tDisk Statistics"
        df -h | grep "%"
    elif [ "$OPTARG" = "M" ]
    then
        echo -e "\t Memory Statistics "
        free -m | awk 'BEGIN{printf "\t\tTotal\tUsed\tFree\n"; OFS="\t" }\
 /Mem/||/Swap/{printf "\t"; print $1,$2,$3,$4}'
    else
       Invalidoptions
    fi;;
  m) Isnumber $OPTARG
     k3sort="sort -nr -k 3"
     echo -e " PID   PPID  MEM  CPU COMMAND "
     ps -Ao pid= -o ppid= -o pmem= -o pcpu= -o comm=|$k3sort|$top;;
  c) Isnumber $OPTARG
     k4sort="sort -nr -k 4"
     echo -e " PID   PPID  MEM  CPU COMMAND "
     ps -Ao pid= -o ppid= -o pmem= -o pcpu= -o comm=|$k4sort|$top;;

esac
done

Output:

[root@localhost blog]# sh sys_monitor2.sh -u
     Currently Logged In Users
root     tty7         2009-09-23 13:48 (:0)
root     pts/2        2009-09-23 14:36 (:0.0)

[root@localhost blog]# sh sys_monitor2.sh -d
Todays Date:   23-Sep-2009       Time:  16:50:38

[root@localhost blog]# sh sys_monitor2.sh -m 5
PID   PPID  MEM  CPU COMMAND
3122  3102  9.6  3.0 firefox
2765  2540  1.9  0.0 nautilus
3849     1  1.7  1.0 ktorrent
2882     1  1.6  0.0 tomboy
2810     1  1.6  0.0 /usr/bin/sealer

[root@localhost blog]# sh sys_monitor2.sh -m
Usage: sys_monitor2.sh [OPTIONS]
OPTIONS:
      -d      for display today's date
      -u      for Logged in users list
      -f ARG  for Disk and Memory Statistics
             (ARG=D for disk statistics; ARG=M for memory statistics)
      -c ARG  for Top CPU consuming process
              (ARG=10 means top 10 process)
      -m ARG  for Top Memory consuming process
              (ARG=10 means top 10 process)
      Note: Only one option at a time and -f,-c and -m require argument