You may consider to use rlwrap for comfortable wor with
sqlplus. Package for Solaris 10 (x86) release you can download . Note rlwrap is dependent on readline library which should be installed first. readline library package.
su -
# gunzip readline-5.1-solaris-x86.gz
# gunzip rlwrap-solaris-x86.gz
# pkgadd -d readline-5.1-solaris-x86 rlwrap-solaris-x86
# exit
echo "alias sqlplus='/usr/local/bin/rlwrap sqlplus'" >> /export/home/oracle/.bash_profile
. /export/home/oracle/.bash_profile ================= bash-3.00# /usr/local/bin/rlwrap ld.so.1: rlwrap: fatal: libreadline.so.5: open failed: No such file or directory Killed