ORA-27121: unable to determine size of shared memory segment

If when you are trying to login to Oracle 10G on linux you get :


ORA-01034: ORACLE not available
ORA-27121: unable to determine size of shared memory segment
Linux Error: 13: Permission denied

This is caused by Oracle installer not setting setuid on $ORACLE_HOME/bin/oracle.
To fix do:


$ cd $ORACLE_HOME/bin
$ chmod 6751 oracle

via http://www.jasonash.com/techblog/index.php/linux/ora-27121-unable-to-determine-size-of-sh