Parsing unflagged parameters in bash script

Calab · 04-06-2010, 10:04 PM

I've searched online and found many examples using getopts, but nothing that clearly explains it use, nor any examples of what I'm trying to do.

I have a script named "process". It can take from 0 to 3 different options. I'd like to be able to handle these options regardless of the order that they are entered.

Syntax:
process [-v] [-d #] [-h|-?] [string]

-v = verbose mode on
-d # = how deep to do the process, expecting a number parameter
-h or -? = show command usage
string = only process lines containing the specified string

I'd like the user to be able to enter the command freestyle. In other words:

process findme
process -d 3 findme
process findme -d 3
process -v findme -d 3
etc..

This is what I'm currently using and it does not meet my needs as it can't handle the string parameter:

Code:

verbose=0;

while getopts vhd: optname
  do
    case "$optname" in
      v)
        verbose=1
        ;;
      d)
        depth="$OPTARG"
        ;;
      h | ?)
        echo "How to use this command"
        exit
        ;;
   esac
  done

How can I process the parameters passed to my script?

grail · 04-06-2010, 10:28 PM

getopts requires your options to have a dash (-) in front of them (although you can string them together ie -abc same as -a -b -c)
and to be single items (ie not a string).
(See here for getopts explanation: http://tldp.org/LDP/abs/html/internal.html#EX33)

This would generally not prove difficult with what you have as your getopts loop processes each option and then
a simple follow up if should easily process your string.

PMP · 04-07-2010, 03:12 AM

Once you are done with processing of arguments

do this

Code:

shift $(($OPTIND - 1))

That is after the end of the while loop of optargs

Now $1, $2 are your normal argument after the flag

catkin · 04-07-2010, 03:32 AM

getopts does not support having arguments before options and any associated option arguments; it supports only

Code:

command [option [option argument]] ... [argument] ...

You may have more luck with the later getopt. Alternatively it may be possible to script your way around it using (referencing and setting) getopts' $OPTIND.

For similar discussion see this LQ thread.