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With the up arrow you get the last commands you typed, and press enter to execute it. If you want to run the same command several times, you can use for-loop ( in bash) for n in {1..3}; do <COMMAND>; done repeats 3 times Another option is watch If you want to repeat a command every x seconds, ideal ...

you can use concat to add to already existing string (varchar,text,...)

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UPDATE table_name SET text_field=CONCAT(text_field,'string to add') WHERE  id='1';

It doesn't work if the value is NULL,
It works with an empty string ('').
So you should replace all NULL values with empty string before.

Yes, it look lik this:

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#Set the IP
case $VALUE in
1)
IP=192.168.1.160
NAME='a';
;;
2)
IP=192.168.1.161
NAME='B';
;;
*)
IP=192.168.1.1
NAME='Default';
;;
esac

in this case $VALUE can be 1 or 2,
anything else will result in default.
I think it is a string compare, so you can use anything.

you can also use:

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echo ${STRING: -1}

Just remember that the last character can sometimes be a whitespace ( space, newline ...)

You can work with a sub-query an UNION:

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SELECT table1.id,union_table.name FROM table1 LEFT JOIN 
   (SELECT id,name FROM table2 UNION SELECT id,title AS name FROM table3) 
   AS union_table ON table1.other_id=union_table.id;

The error is because MYSQL is in strict mode (default) You can Check MYSQL mode SELECT @@GLOBAL.sql_mode global, @@SESSION.sql_mode session You change it with the following query; SET sql_mode = ''; or SET GLOBAL sql_mode = ''; Using the keyword GLOBAL requires super privileges and it affects the op...

There are several ways to run a script on startup/reboot on linux. My favorite : Crontab sudo crontab -e @reboot /home/me/scripts/this.sh Another way to do it, local.d scripts at boot time, add its init.d script to the default runlevel. Enable local.d Scripts rc-service local start and then create y...

MYSQL has changed it type of password (since Mysql 8 ?)
Anyway the easiest solution, is execute the following SQL command on MYSQL

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ALTER USER 'mysqlUsername'@'localhost' IDENTIFIED WITH mysql_native_password BY 'mysqlUsernamePassword';

It should solve your problem.

Are you sure you are sending it to the right account?

sometimes you need to also add the domain name (even if it is not a public domain).

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sendmail user@host.domain.com

are you sending to a user on the server.
Do a test from the client:

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sendmail user@host

and check the logs on the client and on the server.

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