Manual Database Creation scripts

/oracle/product/10.2.0/db  lets say this path exits

 add the below content to .profile (solaris) or .bash_profile(linux)
ORACLE_BASE=/oracle ; export ORACLE_BASE
ORACLE_HOME=/oracle/product/10.2.0/db ; export ORACLE_HOME
PATH=:$ORACLE_HOME/bin:/oracle/product/10.2.0/db/OPatch:/usr/sbin:$PATH:.  ; export PATH
TMP=/tmp; export TMP
TMPDIR=/tmp ; export TMPDIR
ORACLE_SID=orcl; export ORACLE_SID

 .cshrc (solaris) or .bashrc (linux)
setenv ORACLE_BASE /oracle
setenv ORACLE_HOME /oracle/product/10.2.0/db
setenv PATH $ORACLE_HOME/bin:/oracle/product/10.2.0/db/OPatch:/usr/sbin:$PATH
setenv TMP /tmp
setenv TMPDIR /tmp
setenv ORACLE_SID orcl 

below is the content for initorcl.ora ($ORALCE_HOME/dbs)
*.audit_sys_operations=FALSE
*.audit_trail='TRUE'
*.background_dump_dest='/oracle/admin/orcl/bdump'
*.control_files='/oracle/oradata/orcl/control01.ctl','/oracle/oradata/orcl/control02.ctl','/oracle/oradata/orcl/control03.ctl'
*.core_dump_dest='/oracle/admin/orcl/cdump'
*.db_cache_size=104857600
*.db_files=230
*.db_name='orcl'
*.instance_name='orcl'
*.job_queue_processes=10
*.log_archive_dest_1='LOCATION=/App1/oracle/admin/orcl/arch'
*.log_archive_start=TRUE
*.optimizer_mode='ALL_ROWS'
*.pga_aggregate_target=73400320
*.processes=100
*.sessions=100
*.sga_max_size=900m
*.sga_target=500m
*.undo_management='AUTO'
*.undo_retention=10800
*.undo_tablespace='UNDOTBS1'
*.user_dump_dest='/oracle/admin/orcl/udump'
 now startup the databse 

$sqlplus / as sysdba

sql> startup pfile=path/initorcl.ora nomount

sql>here execute the below script 

create database orcl
datafile '/oracle/oradata/orcl/system01.dbf' size 1024m autoextend on extent management local
undo tablespace UNDOTBS1 datafile '/oracle/oradata/orcl/undotbs01.dbf' size 512m autoextend on
sysaux datafile '/oracle/oradata/orcl/sysaux01.dbf' size 512m
default temporary tablespace temp tempfile '/oracle/oradata/orcl/temp01.dbf' size 512m
character set WE8ISO8859P1
logfile
group 1 ('/oracle/oradata/orcl/redo01.log') size 10m,
group 2 ('/oracle/oradata/orcl/redo02.log') size 10m,
group 3 ('/oracle/oradata/orcl/redo03.log') size 10m;

now database in open state.