Okay the title is not very good so i will explain(sorry for my english i am from a galaxy far far away )
Let's suppose i have a dir named MainBla that contains four dirs named bla1 bla2 bla3 bla4 and each one of these dirs has a file(i believe it's the same procedure if each one of the bla dirs contains other dirs that contain files etc).
I am writing a script which takes optional parameters:
$1: the path that MainBla is found
$2: one of the bla folders in order to do whatever my script does with the file that bla contains.

So one call might be ./script.sh /..../MainBla bla1.
Let's suppose now that i want to change that into
./script /.../MainBla bla1-bla3...in that case $2 argument is the range of dirs i want to work with(bla1,bla2,bla3 but not bla4).how can i make the script change from bla1 to bla2 and then to bla3?
(this can be expanded for random number of dirs)
again excuse me for my poor english.if you have any questions please ask me.
Thank you

I would do it in a different way, an easier way.

The shell can expand parameters such as bla{1..3} to 3 parameter: bla1 bla2 bla3. If you call your script with bla{1..3} instead of bla1-bla3, then your work is already done for you. In your script you can access the command line parameters as $2 $3 $4 etc... You can loop over all of them with a code like this:

shift
for bla in $@
do
echo $bla
done

This is how I run it, and the output I get:
./bla.sh blaMain bla{1..3}
bla1
bla2
bla3


Note that '$@' is equivalent to '$1 $2 $3'... which is why I call 'shift' in the beginning to shift the parameters 1 place left ($2 will become $1, $3 will become $2 and so on...). You can also know how many parameters your script got on the command line with $#.

thank you very much for your answer.the truth is i already know that procedure,so i am not interested in the easiest way but in the particular one i am describing above,which i think needs string manipulation...if you have any suggestion on that,pls tell me.thnks again!


//i think i have some progress here.when i finish i will write my results

What about google?

http://tldp.org/LDP/abs/html/string-manipulation.html

(Or in other words, what have you tried, already?)

you are not gonna believe this.i was just checking that page!i managed to separate the parameter bla1-bla3 in bla1 and bla3.then i create a path with each one of these parameters...now i am thinking how i am going to make the script change from bla1 to bla2 and then to the upper bound which is bla3...

Problem solved:

First i define which will be the lower bound and the upper bound from the dirs included in MainBla

MainBla=$1
bla_general=$MainBla"/"$2
string=$2
bla_lower_bound=$MainBla"/"${string%-**}
bla_upper_bound=$MainBla"/"${string#**'-'}


for lalala in $( \ls $MainBla)
do
bla_lower_bound=$MainBla"/"$lalala
if [[ "$bla_lower_bound" < "$bla_upper_bound" ]]||[[ $bla_lower_bound == "$bla_upper_bound" ]]
then
cd $bla_lower_bound

And after this i begin a second "for" that gets into the specific dir that i want to work every time...