Mysql - backup all databases

$ mysqldump -u root -p --all-databases > alldb_backup.sql

Migrate Atlassian Confluence local version 4.0 to OnDemand version 5.0

1. Backup current wiki data to XML.
2. Upgrade local 4.0 to 5.0 version.
3. Subscribe Confluence OnDemand service.
4. Export space from local wiki, one by one, since OnDemand version cannot restore the whole backup in one click.
5. Import spaces to OnDemand.
6. Done.
   

Mac reset password

1. Press and Hold Command-R when startup.
2. Open terminal.
3. >resetpassword

Windows 7 hosts file

C:\Windows\System32\driven\etc\hosts

Git - remove or delete tag and remote tag

git tag -d 12345  git push origin :refs/tags/12345

Rails - update attr_readonly field from sql

The easiest way to update field with attr_readonly is to update by
database sql.

$> psql -d xxx -U xxx
xxx> update ... set ... where ...