NLS_COMP and NLS_SORT

Hi all, I'm looking for character sets and collation with Oracle. About character set from the shell I have:

$ locale character

utf-8

and

$ echo $NLS_LANG

AL32UTF8 Now I'm also looking for collation, ie the comparaison between strings and I've found other two environment variables: NLS_COMP and NLS_SORT, but I don't understand how to set them permanently (if it's possible). If I use an alter session statement to set NLS_SORT and NLS_COMP the change is conscripted to a single user session. So, exists a way to set the two paramethers permanently?

Thanks, Simone Saravalli

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