looking for help in writing a bash script

onepostonly · 10-05-2008, 04:12 PM

I have read http://linuxcommand.org , specially http://www.linuxcommand.org/wss0130.php , and what I am looking to do, is something of the likes of

Code:

my_script -w websiteadress -f filename

and for this, what I need is, "websiteadress" can either work by doing '-w "websiteadress"', or '--website="websiteadress"', and the same for '-f "filename"', that equals '--filename="filename"', there should be only one more option, which is '-h', the same as '--help', that should print the scripts usage, and should also be printed, in case '-f' or '-w' parameters are missing, both are mandatory, and should translate to constants, so, later in the script, values entered can be translated to something as ${FILENAME} and ${WEBSITEADRESS}, from there on, I think I already know how to make it work

I apologise for the work, I understand it may be a somewhat big request, but I believe that someone knowledgeable, helping on how to do this correctly, the most efficient way, on a script that will prove useful to me, will have better results, even on future projects, than reading on an unrelated script subject, and trying to adapt it

Note, I also know that I could accomplish this with something like setting '$1' and '$2', but this would not be as effective, as would not give any help on it's usage, and both parameters would have to be entered on the same order, every time

i92guboj · 10-05-2008, 04:27 PM

Use a while loop, then case, and shift. Like this:

Code:

# loop until number of arguments is zero
while [ $# -ge 1 ]; do
case "$1" in
-h|--help)
# show help text and exit
exit 0
;;
-f|--filename)
# shift the positional parameters
shift
# now, what was in $2 is now $1
FILENAME="$1"
;;
-w|--website)
shift
WEBSITE="$1"
;;
esac
# advance to the next parameter
shift
done

onepostonly · 10-05-2008, 05:57 PM

Thank you for your quick help
If I may make an observation, there is something missing in the example you gave me, I was getting an error, and examining the code, found it was after 'exit 0', you forgot ';;', I also believe the ';;' after 'WEBSITE="$1"' was not necessary, I think it was giving me problems later in the script
I also used your code as reference, and following the webpage I mentioned before, from http://linuxcommand.org, I organized it a little bit, and added the other options I wanted, such as printing usage when no arguments are given, and making both '-f' and '-w', mandatory

Code:

#!/bin/bash

##### Function

function usage
{
echo 'Usage: my_script [-f filename | --filename filename] [-w websiteadress | --website websiteadress]'
}


##### Main

# Show usage and exit, if no arguments are given
if [ "$1" = "" ]; then
        usage
        exit 1
fi

# loop until number of arguments is zero
while [ "$1" != "" ]; do
        case "$1" in
                -f | --filename )       shift
                                        FILENAME="$1"
                                        ;;
                -w | --website )        shift
                                        WEBSITE="$1"
                                        ;;
                -h | --help )           usage
                                        exit 0
                                        ;;
                * )                     usage
                                        exit 1
        esac
        shift
        done

# Show usage and exit, if either '-f' or '-w' are missing
# First, check for '-f'
if [ "${FILENAME}" = "" ]; then
        echo 'my_script: "--filename" option is missing'
        exit 1
fi
# Then, check for '-w'
if [ "${WEBSITE}" = "" ]; then
        echo 'my_script: "--website" option is missing'
        exit 1
fi

Until now, everything is working as I want, I've been testing and altering it since I saw your response, and everything seems to be coming together pretty well, thanks again for your help

i92guboj · 10-05-2008, 06:42 PM

Quote:

Originally Posted by onepostonly

Thank you for your quick help
If I may make an observation, there is something missing in the example you gave me, I was getting an error, and examining the code, found it was after 'exit 0', you forgot ';;',

Yup hehe, I was in a hurry and missed it. I'll edit my post so no one gest confused about it in the future.

Quote:

Until now, everything is working as I want, I've been testing and altering it since I saw your response, and everything seems to be coming together pretty well, thanks again for your help

Glad to be of any help.