Answer:

A newer version of MySQL use upstart to autostart when system bootup, to disable it

# sudo mkdir /etc/init.disabled
# sudo mv /etc/init/mysql.conf /etc/init.disabled/

Answer:

You can use the following method to generate random string into a collection in MongoDB:

function randomString() { 
        var chars = 
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz"; 
        var randomstring = ''; 
        var string_length = 100;
        for (var i=0; i<string_length; i++) { 
                var rnum = Math.floor(Math.random() * chars.length); 
                randomstring += chars.substring(rnum,rnum+1); 
        } 
        return randomstring; 
} 

for(var i=0; i<2000000; i++){db.test.save({x:i, data:randomString()});} 

Answer:

In you mongo shell, execute the following command:

var sum = 0; db.getMongo().getDBs()["databases"].forEach(function(x) { sum += db.getMongo().getDB(x.name).stats().indexSize }); print(sum)

Answer:

Edit the file "/etc/default/locale" to the locale you want.

Answer:

Use the -L or --copy-links option, e.g.

rsync -avuz --copy-links -e ssh /home/john 192.168.1.5:/data/backup/

Answer:

To move more efficiently in bash shell, you can use the following short cuts

Meta + f (move forward by a word)
Meta + b (move backward by a word)

The Meta key is the Alt key under most systems, on Mac, you would need to enable "use option as meta key" in the Terminal's Preference.

Answer:

The answer is no, you can't.

You need to use other alternative like rsync.

Reference: https://bugzilla.mindrot.org/show_bug.cgi?id=485

Answer:

To echo single quote (using single quote only), you can try

# echo foo
foo
# echo \'''foo
'foo

Answer:

To see how long a MongoDB instance was running, you can login into the mongo shell, and enter

db.serverStatus().uptime / 3600

The above command reply the value in term of hours.

Answer:

The easiest way is login into the MongoDB using the shell, enter the command:

db.adminCommand({getLog: "startupWarnings" })