MySQL backup and manual execution of shell scripts are OK, and crontab scheduled execution fails

Backup scripts

vim mysql_backup.sh

#!/bin/bash

source /etc/profile
source ~/.bash_profile
 
#  Saved Directory 
data_dir="****"
#  Save the name of the file , Be careful date Yes, it is # Backquotes # Wrapped up  
data_name="bak_`date +%Y%m%d%H`.sql"
 
if [ ! -d $data_dir ]; then
  mkdir -p $data_dir
fi
 
# mysqldump Backup command 
# -uroot    user name 
# -p123456  password 
# test  Database name 
mysqldump -uroot -p123456 test > $data_dir/$data_name
 

Backup file

vim remove_backup.sh

#/bin/bash

source /etc/profile
source ~/.bash_profile
#  Saved Directory 
data_dir="****" 

#  Delete 7 Days ago backup files 
find $data_dir -mtime +7 -type f -name "bak_*.sql" ;

atime、ctime、mtime

atime： Access time （access time）, It refers to the time when the file or directory was last accessed ;
ctime： Change the time （change time）, It refers to the last change of file or directory ( What's changed is the original data, that is : attribute ) Time for ;
mtime： Modification time （modify time）, It refers to the time when the file or directory was last modified ;
Use stat Command to view three time values : Such as stat filename

find Find based on time

mtime The parameters are as follows ：
-mtime n according to ⽂ Change the time to find ⽂ Pieces of ,n Integers .
n surface ⽰⽂ The change time distance is n God
-n surface ⽰⽂ The change time distance of the piece is n Within days
+n surface ⽰⽂ The change time distance of the piece is n Before the day
 

for example ：
-mtime 0 surface ⽰⽂ The modification time distance of this document is currently 0 Days of ⽂ Pieces of , That is less than the current time 1 God （24⼩ when ） Inside ⽂ Pieces of .
-mtime 1 surface ⽰⽂ The modification time distance of this document is currently 1 Days of ⽂ Pieces of , That is, from the current time 1 God （24⼩ when －48⼩ when ） Of ⽂ Pieces of .
-mtime＋1 surface ⽰⽂ The modification time of this document is ⼤ On 1 Days of ⽂ Pieces of , That is, from the current time 2 God （48⼩ when ） In addition to the ⽂ Pieces of
-mtime -1 surface ⽰⽂ The modification time of this document is ⼩ On 1 Days of ⽂ Pieces of , That is, from the current time 1 God （24⼩ when ） Within ⽂ Pieces of
 

Grant authority

chmod   755 ***.sh

Timing task

crontab -e

0 */2 * * * root  mysql_backup.sh # Every time 2 Hours 

0 1 * * * root remove_backup.sh #  Every morning 1 spot , Automatically delete 7 Days ahead backup 

shell The script can be executed manually ,crontab Scheduled execution failed

Problem description ：

   Shell The script can be executed manually and run normally , And get the right results ; Use Crontab When scheduling ,Shell The amount of result data from the execution of the script is 0.

reason ：

     Linux Next use crontab Executing scheduled tasks will not default from the user profile Read the environment variable parameters from the file , So it often leads to success when executing a script manually , But to crontab When you try to make it execute regularly, you will make an error . This is because the user logs in Linux When operating the system ,”/etc/profile”, “~/.bash_profile” And other configuration files will be executed automatically , and crontab The configuration file may not be executed during scheduled scheduling .
 

Solution ：

Shell The script defaults to  #!/bin/sh  start Line break Add... On the first line after

source /etc/profile
source ~/.bash_profile