Sorry Scrutinizer,

You 're right, it's not clear what I said.
I start again.

This my_script.sh

Code:

function f1 {


 } 
 egrep -v '^#' list_file \
 | while read arg1 arg2 arg3 arg4; do 
  f1 $arg1 $arg2 $arg3 $arg4   
done

For information
My function f1 is going to grep the lines between 2 hours (10 to 20) and (08 to 10) respectively in srv4's srv_log and srv3's srv_log.
Then this function f1 will put the results into 2 files named srv4.srv_log.10H-20H and srv3.srv_log.08H-10H.

Here's how I'd like my script works

1st case : I create the list_file before

Then i launch

Code:

./my_script list_file

2nd case i launch the script without list_file

Code:

./my_script

I would like my_script creates automatically list_file with these comments

And at the prompt echo
Third case
I launch the script with these parameters

Code:

./my_script 10 20 srv_log srv4

I would like my_script creates automatically list_file with these comments.
I hope I was clear enough now
I'm sorry again. Thank you for your response.
.