Passing options to a bash script

Shell Programming and Scripting
1

I'm just not sure where to start looking into this. I want to be able to create switches for my script. Back in the day I'd make my scripts interactive...you know:

echo "what report do you want"
echo "A)boxes with errors"
echo "B)boxes with more than 5 errors"
echo "C)Service groups that have thrown errors"
read $1
if ...

but now that seems kind of amateurish. I'd rather have a script where errorreport.sh -c made a list of boxes, errorreport.sh -m listed boxes with multiple errors and so on.

I'm not asking anyone to give me a step by step on how to do this, I'd rather learn by doing, but I don't even know where to start. I've tried googling "adding switches to bash scripts" and the like, and I've been scanning my o'reiley books, but at quick glance I don't see what I'm looking for.

If anyone could tell me where I might at least start reading up on this I'd appreciate it.

2

I think that you want "getopts", which is a bash built-in command.

3

You can do something as the following, you can also add additional logic to force a user to enter good input, so the script does not exit, but I'll leave that to you.

#!/bin/sh

echo "What report do you want?"
echo "A) boxes with errors"
echo "B) boxes with more than 5 errors"
echo "C) Service groups that have thrown errors"
read CHOICE

case $CHOICE in
        A|a)
                echo "Choice was $CHOICE"
                ;;
        B|b)
                echo "Choice was $CHOICE"
                ;;
        C|c) 
                echo "Choice was $CHOICE"
                ;;
          *)
                echo "Valid Choices are A,B,C"
                exit 1
                ;;
esac
4

This might also help you..Look out for $1=-g option.

# # # # # # # # # # # #
#     main section
# # # # # # # # # # # #

  print "script $(basename $0) executing $(date +%Y/%m/%d\ %H:%M:%S) \n"

#
#  only allow this script to be run by the root user
#
  if ! id | grep -q "uid=0(root)" ; then
    print "ERROR:  must be root in order to run this script"
    exit 1
  fi

  if [[ "$PLEX_ROOT" = "/claims/amxw" ]]; then
    if [[ "$NLROOTDIR" != "/claims/amxw" ]]; then
      print "ERROR: NLROOTDIR must be set to /claims/amxw in order to create a plex"
      exit 1
    fi
  fi

  if [[ "$1" = "-g" ]]; then
    shift
    print "You are obviously a plex god and have chosen to skip the approved naming convention.  Please proceed, your eminence"
    print
    mode=GOD
  else
    mode=MORTAL
  fi

  plexname=$1

  if [[ -z $plexname ]]; then
    print "ERROR: plex name isn't specified"
    exit 1
  fi

  if [[ "$mode" = "MORTAL" ]]; then
    if ! print $plexname | grep -q ^plex ; then
      print "ERROR: plex name must begin with 'plex' and be at least 9 characters"
      exit 1
    fi
  fi