Append current date to the filename via Cron?

Question

I've created a Cron task at my webhost to daily backup my database and I would like it to append the current date to the filename.

My Cron job looks like this

mysqldump -u username -pPassword db_name > www/db_backup/db_backup+date%d%m%y.sql

But the file I get is this: db_backup+date no file extension or date.

I've also tried this command

mysqldump -u username -pPassword db_name > www/db_backup/db_backup_'date +%d%m%y'.sql

but that doesn't even give an file output.

What is the right syntax for getting the date appended to my file??

score 109 · Accepted Answer · edited Jun 15 '21 at 12:56

109

* * * * * echo "hello" > /tmp/helloFile_$(date +\%Y\%m\%d\%H\%M\%S).txt

You just need to escape the percent signs.

Other date formats: http://www.cyberciti.biz/faq/linux-unix-formatting-dates-for-display/

edited Jun 15 '21 at 12:56

General Grievance

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answered Aug 16 '13 at 21:49

ethanneff

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Working on CentOS 6.6. */10 * * * * /usr/bin/php -q /var/www/script.php > cron-job-log-$(date +\%Y\%m\%d\%H\%M\%S).txt – ursuleacv Apr 01 '15 at 16:47
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The @ursuleacv answers works as expected. Here is my sample cron command: `08 10 * * * mysqldump -uYeBeSis_X2 -pPASWORDTHING dbName > /var/www/yebesis/mysqly/$(date +\%Y_\%m_\%d_\%I_\%M_\%p)_yebesis.sql` – caglaror Nov 21 '17 at 08:13
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I guess he meant "escape percentages" because parentheses aren't escaped. After I escaped the percentage symbols it worked in my cron. – Miguel Ortiz Mar 04 '21 at 13:59
Note to self: BSD's `date` doesn't support the very convenient `-I` – Sridhar Sarnobat Jul 26 '21 at 06:58
Is it possible to set date to env variable to prevent writing it twice(for stdout and stderr)? both $() and backtikcs failed. – quant2016 Dec 15 '22 at 09:00

score 31 · Answer 2 · edited Feb 02 '12 at 17:12

31

You should use `` instead of '' around the command you want to execute to generate the current date for your filename.

edited Feb 02 '12 at 17:12

Zsolt Botykai

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answered Feb 02 '12 at 10:30

Fonzarely

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could you edit the answer or someone provide a more exact example in the comments? – Jon Grah Jan 18 '18 at 05:36
```> proposed_file_name_`date + \%d\%m\%y`.sql``` – tfantina Jul 02 '20 at 17:33

score 10 · Answer 3 · edited Apr 27 '16 at 14:13

10

You must escape the format and use evaluation

mysqldump -u username -pPassword db_name > www/db_backup/db_backup_`date +\%d\%m\%y`.sql

edited Apr 27 '16 at 14:13

Paul Roub

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answered Apr 27 '16 at 14:12

RomAndNonES

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score 7 · Answer 4 · edited Dec 30 '15 at 16:05

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I need to create a new log file every time command is executed. So every day I should have a log like this /home/me/Logs/power_20151230.log The crontab line that I use is this:

00 8 * * * /home/me/power.py ON >> /home/me/Logs/power\_`date +20\%y\%m\%d`

Note the underscore character must be escaped too.

edited Dec 30 '15 at 16:05

huzeyfe

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answered Dec 30 '15 at 15:13

edison

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It's not necessary to prepend `20` in front of `\%y`. It's better to use the upper-cased Y like this: `\%Y`. – thexpand Mar 22 '18 at 09:51

Append current date to the filename via Cron?

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