Guys,
thanks for all the help. It is not a home work although perfectly sounds that way. I have a long sql file which has many individual sql statements like analyze table (one liner). so what we want to do is to break the master script into 5 individual script so we could run 5 sqlplus sessions at a time. However it could be done with other way but this 5 sqlplus sessions is now the interest to my company.

I used stuffs like you guys mentioned: both sed and split:for example:

split -b1024b bigfile and it created a bunch of xxa xxb types which could be renamed to sql file and very well run without trouble.

sed was useful too.

thanks.