Configuration files often come with a lot of commentary. Documentation is always good, but sometimes you just want the red meat. Here’s how to see a file without all the ‘#’ commentary.

grep ^[^#] /etc/someconfig.conf

Golden.

If you want to download a YouTube video, here’s how. First install the youtube-dl binary and the associated codecs…

sudo apt-get install youtube-dl ffmpeg libavcodec-extra-53

Once it installs, get your YouTube URL and simply run the command..

youtube-dl http://www.youtube.com/watch?v=Z3W05t79ZWY

to download the video. There are a load of other options you can use which are all shown thus..

youtube-dl --help

Conveniently, the youtube-dl command also does on-the-fly conversion of downloaded videos to just the .mp3 version for audio playback, thus…

youtube-dl http://www.youtube.com/watch?v=Z3W05t79ZWY -x --audio-format mp3

Where -x means ‘eXtract’. Again, there are a load of options here.

Simple command that you sometimes need. Obviously this runs from the mysql client prompt, so open a command line and type

mysql -u root -p

and then enter the root password for your mySQL database.

Then, switch to your database…

USE yourdatabasename;

An now, all you need is..

SHOW columns FROM your_table;

OR

SELECT COLUMN_NAME' FROM 'INFORMATION_SCHEMA'.'COLUMNS'
WHERE 'TABLE_SCHEMA'='YOUR_DATABASE'
AND 'TABLE_NAME'='YOUR_TABLE';

Nice.

You appear to be coming from the ip address below..

Simple. Fire these commands to reset your user and also secure their gpg keys / files as well.  The user name will be substituted automatically.

sudo chown -R $USERNAME:$USERNAME /home/$USERNAME
sudo find ~ -type f -print0 | xargs -0 chmod 0640
sudo find ~ -type d -print0 | xargs -0 chmod 0750
sudo chmod 600 ~/.ssh/id_rsa
sudo chmod 740 ~/Desktop/*.desktop
sudo chmod 600 ~/.gnupg/*
sudo chmod 700 ~/.gnupg

Very simple. Use the following commands..

Backup to an external file.

On the *nix command line, just run..

mysqldump -u root -p database_name > /path/to/database_dump_file.sql

Punch in the password for root (in this case) and the backup is output to the file database_dump_file.sql. It’s ASCII so it can be edited if needed.

Restore from an external file..

mysql -u root -p database_name < /path/to/database_dump_file.sql

Typed the password and that's it, finished.

Need the database names quickly?

Log in to the database as ususal with the command at the *nix command line.

mysql -u root -p

And then issue the following at the prompt..

mysql> show databases;

and you get this....

+----------------------+
| Database             |
+----------------------+
| information_schema   |
| largedump            |
| dspam                |
| mysql                |
| performance_schema   |
| testdata             |
| testdata_1           |
| dataset_4            |
| dataset_2            |
+----------------------+
9 rows in set (0.01 sec)