I had to set a cron job to back up mysql database and its format I wanted is like this
back_up_YYYY_MM_DD.sql
And here was my first initial configuration that I added to /etc/crontab
00 11 * * * a_user mysqldump -u root -pSomePass db > /home/a_user/www/sql_backup/back_up_`date +%Y_%d_%m`.sql
Actually, I noticed a strange syntax color at the end of the line in Vim. I thought it is just misparsing so that I ommited it.
And here was the output in /var/log/syslog
Jan 4 11:00:01 a_user CRON[3427]: (a_user) CMD ( mysqldump -u root -pSomePass db > /home/a_user/www/sql_backup/back_up_`date +)
Something was wrong as you can see; it was not complete.
In order to fix this, I had to escape the ‘%’ sign
00 11 * * * a_user mysqldump -u root -pSomePass db > /home/gizmo/www/sql_backup/back_up_`date +\%Y_\%d_\%m`.sql
Now, everything works fine :D