Shell Programming and Scripting

Hi,
I'd like to run a script with an optional starting point.
Meaning that if no parameter for the script => Do everything, otherwise start from the point specified in the parameter and continue till the end.

I thought of using the "case ..." but I have no result.
Script:
# ---------------
START_POINT=$1
if [ "$START_POINT" = "" ]
then
START_POINT="a"
fi
echo ">$START_POINT<"
case $START_POINT in
"a") echo "Running >a<!";;
"b") echo "Running >b<!";;
"c") echo "Running >c<!";;
"d") echo "Running >d<!";;
default) echo "Wrong value for starting point";;
esac
return
# ---------------
result expected:
> script [nothing]
Running >a<!
Running >b<!
Running >c<!
Running >d<!

> script c
Running >c<!
Running >d<!

> script k
Wrong value for starting point

Please provide some help.
Thanks in advance.
Regards!

Alternatively, you can write functions to do specific tasks and then call them as per needed. If no arguements are passed to the script, call all the functions.

Yes, that'a an alternative.
My main issue is to manage the starting point in the script, not running every thing.

Thanks.

if you are using tcsh, then you can take help of goto to do what you want. bash and ksh does not support goto.

Also, have a look at this (that person might have solved his problem without using goto)

It's much more simpler if you use numbers as starting points:

Code:

START_POINT="$1"

if [ ! "$START_POINT" ]; then START_POINT=0; fi

if [ "$START_POINT" -le 10 ]; then echo "Running 10!"; fi
if [ "$START_POINT" -le 20 ]; then echo "Running 20!"; fi
if [ "$START_POINT" -le 30 ]; then echo "Running 30!"; fi

Then you specifiy a parameter and, if the number is lesser than the execution step, the code will be executed.

Put the case-esac construct in a while loop.

Code:

[/tmp]$ cat test.ksh
#! /bin/ksh
#

while :
do
    case $1 in
        "") set -- a ;;
        "a") echo "a" ; set -- b ;;
        "b") echo "b" ; set -- c ;;
        "c") echo "c" ; set -- d ;;
        "d") echo "d" ; break ;;
        *) echo "Wrong" ; break ;;
    esac
done
[/tmp]$ ./test.ksh
a
b
c
d
[/tmp]$ ./test.ksh a
a
b
c
d
[/tmp]$ ./test.ksh c
c
d
[/tmp]$ ./test.ksh d
d
[/tmp]$ ./test.ksh z
Wrong
[/tmp]$ ./test.ksh abcd
Wrong
[/tmp]$

Perfect!
That's it.

Thanks a lot vino .

Thanks also to others, I will use some answers for something else .

Regards.

Antonio.