Whenever I perform select statements in the command line tool it doesn't use all of the space.
I've modified buffer size and window size and it just doesn't work.
sqlplus does not automatically adjust its output width to fit your terminal window width. You need to change the width with something like set linesize 120
You might want to peruse the SQL*Plus documentation for more information on controlling output format.
Taken from the Oracle Forums:
If you want to make this permanent, in your DB/Oracle client directory look for the file glogin.sql in $ORACLE_HOME/sqlplus/admin and add this line:
SET LINESIZE 9999;
Now it will be set whenever you login into SQL Plus.