Unable to open env file: /etc/default/locale

To fix
"Unable to open env file: /etc/default/locale: No such file or directory"
in /var/log/auth.log, run:

update-locale

vim: convert the ^M linebreak to 'normal' linebreak

^M is ctrl+v and ctrl+M
:%s/^M/\r/g

mysql group by and having

mysql> select CASNumber, count(CASNumber) as ccas from compounds group by CASNumber having ccas=1 order by ccas ;

sed: -e expression #1, char 24: unknown option to `s'

When you call sed in ruby, you may get this error message

here is the ruby code

def update_server (conf_file_path, config )
puts "update #{conf_file_path}"
%x[sed "s/drs_db.*\/drs_db/drs_db mmmmmmmm \/drs_db/g" #{conf_file_path}]
end

correct:
def update_server (conf_file_path, config )
puts "update #{conf_file_path}"
%x[sed "s/drs_db.*\\/drs_db/drs_db mmmmmmmm \\/drs_db/g" #{conf_file_path}]
end

add a line in a file

add a line after line: [mysqld]
sed -i '/\[mysqld\]/ a\bind-address = 6.31.83.19' test.cnf

how to check mysql version

mysql> SELECT version();
+--------------------+
| version() |
+--------------------+
| 5.0.51a-3ubuntu5.7 |
+--------------------+
1 row in set (0.00 sec)

mysql> status
--------------
mysql Ver 14.12 Distrib 5.0.51a, for debian-linux-gnu (i486) using readline 5.2

Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 5.0.51a-3ubuntu5.7 (Ubuntu)
Protocol version: 10
Connection: Localhost via UNIX socket
Server characterset: latin1
Db characterset: latin1
Client characterset: latin1
Conn. characterset: latin1
UNIX socket: /var/run/mysqld/mysqld.sock
Uptime: 153 days 19 hours 36 min 16 sec

enable Telnet client in Windows Vista

1. Open the Programs and Features Control Panel
2. Select "Turn Windows features on or off."
3. Select the Telnet Client option and click OK.