Misc Notes

Securely delete files in linux:

# srm --help

# shred --help

---------

Bash history tweaks:

1) Increase history size in Redhat / Fedora / CentOS:

# vim /etc/profile
...
HISTSIZE=100000
...

2) Append history from multiple terminals:

# vim /etc/bashrc
    ...
    fi
    # Turn on append history
    shopt -s histappend
    history -a
    # Turn on checkwinsize
    ...

---------

Copy your public key to a remote host:

$ ssh-copy-id -i ./.ssh/id_rsa.pub remote.domain.com

Modify MySQL variables without restarting the server

Reminder note on changing MySQL variables live and without restarting the service.

mysql> show global variables where variable_name like '%engine%';
+---------------------------+--------+
| Variable_name             | Value  |
+---------------------------+--------+
| engine_condition_pushdown | ON     |
| storage_engine            | MyISAM |
+---------------------------+--------+
2 rows in set (0.00 sec)

mysql> SET GLOBAL storage_engine=InnoDB;
Query OK, 0 rows affected (0.00 sec)

mysql> show global variables where variable_name like '%engine%';
+---------------------------+--------+
| Variable_name             | Value  |
+---------------------------+--------+
| engine_condition_pushdown | ON     |
| storage_engine            | InnoDB |
+---------------------------+--------+
2 rows in set (0.00 sec)

Very simple, but I can never remember this and it tends to be buried somewhere in MySQL's massive documentation.