Notes on daily bash Dec-07 2020

 https://unix.stackexchange.com/questions/42898/find-any-lines-exceeding-a-certain-length

Get lines exceeding a certain length.

grep '.\{80\}' file

perl -nle 'print if length$_>79' file

awk 'length>79' file

sed -n '/.\{80\}/p' file

Get the max length line

wc -L brake_input.model.dat

Get nth line:

sed 'NUMq;d' file

If you have NUM in a variable, you will want to use double quotes instead of single:

sed "${NUM}q;d" file

https://stackoverflow.com/questions/6022384/bash-tool-to-get-nth-line-from-a-file

Assuming you need lines 20 to 40,

sed -n '20,40p;41q' file_name => not work as expected

or

awk 'FNR>=20 && FNR<=40' file_name

This one work:

sed -n -e '10,100p' input.txt > output.txt

https://gist.github.com/simofacc/061aaf189a559a0817bf

https://stackoverflow.com/questions/13294341/create-slug-to-include-id-and-title-when-insert-record-php-mysql

CREATE TRIGGER trigger_name BEFORE INSERT ON table

FOR EACH ROW SET slug = CONCAT(NEW.title, "-", NEW.id);

CREATE DEFINER=`[USER_NAME]`@`%` TRIGGER `[DATABASE_NAME]`.`Slug` BEFORE INSERT ON `[TABLE_NAME]`.`games` FOR EACH ROW 

BEGIN

IF NEW.slug IS NULL THEN

    SET NEW.slug = LOWER(TRIM(NEW.name));

    SET NEW.slug = REPLACE(NEW.slug, ':', '');

    SET NEW.slug = REPLACE(NEW.slug, ')', '');

    SET NEW.slug = REPLACE(NEW.slug, '(', '');

    SET NEW.slug = REPLACE(NEW.slug, ',', '');

    SET NEW.slug = REPLACE(NEW.slug, '\\', '');

    SET NEW.slug = REPLACE(NEW.slug, '?', '');

    SET NEW.slug = REPLACE(NEW.slug, '\'', '');

    SET NEW.slug = REPLACE(NEW.slug, '&', '');

    SET NEW.slug = REPLACE(NEW.slug, '!', '');

    SET NEW.slug = REPLACE(NEW.slug, '.', '');

    SET NEW.slug = REPLACE(NEW.slug, '&euro;', '');

    SET NEW.slug = REPLACE(NEW.slug, 'euro;', '');

    SET NEW.slug = REPLACE(NEW.slug, ' ', '-');

    SET NEW.slug = REPLACE(NEW.slug, '--', '-');

    END IF;

END;

https://stackoverflow.com/questions/8295131/best-practices-for-sql-varchar-column-length

Some cool desc on varchar length

https://stackoverflow.com/questions/13476029/multiple-table-select-vs-join-performance

Some CI model get column, p-key...

https://stackoverflow.com/questions/10258128/how-to-get-field-names-of-mysql-table-in-codeigniter

Good point

https://stackoverflow.com/questions/54379695/delete-large-amount-of-rows-from-mysql-table-is-very-slow