Crond Daemon implements timing monitoring of the size of a process that occupies memory

1) Add a scheduled task

CRONTAB-E will use an editor to open a file, and then enter the scheduled tasks to be performed, after saving, under/var/spool/cron/crontabs/, a file named after the user name will appear.

2) How to add a scheduled task

Each row in the file contains six fields, the first five of which are the time the specified command was executed, and the last field is the command to be executed.
Spaces or tabs are used to separate each field. The format is as follows:
Minute hour day-of-month month-of-year day-of-week commands

In addition to the numbers there are several special symbols that are "*", "/" and "-", ",", * represent all the values within the range of the number, "/" for each meaning, "/" for each of the 5 units, "-" represents from a number to a number, "," separate several discrete numbers.

Several examples:  
every morning at 6  
0 6 * * echo "Good morning." >>/tmp/test.txt//Note simply Echo, no output from the screen Because cron emails any output to Root's mailbox.

  every two hours,
0 */2 * * * echo "has a break now." >>/tmp/test.txt  

11 o'clock to 8 a.m. every two hours and early Eight o '  
0 23-7/2,8 * * * echo "have a good dream" >>/tmp/test.txt

4th per month and Monday to Friday, three a.m. 11  
0 4 * 1-3 command line

January 1 morning 4  
0 4 1 1 * command line Shell=/bin/bash Path=/sbin:/bin:/usr/sbin:/usr/bi n Mailto=root//If there is an error, or if there is data output, the data is sent to this account as mail home=/ 

executes scripts within/etc/cron.hourly per hour
"* * * * Root run-parts/ Etc/cron.hourly
Execute scripts within/etc/cron.daily every day
4 * * * root run-parts/etc/cron.daily 

Perform/etc/every week Script within cron.weekly
4 * * 0 root run-parts/etc/cron.weekly 

Execute script   within/etc/cron.monthly per month;
42 4 1 * * Root run-parts/etc/cron.monthly 

Note: "Run-parts" is the parameter, if you remove this parameter, you can write a script name to run, instead of the folder name.

3) Problem: In the embedded development, found embedded Linux system input CRONTAB-E error

Crontab:chdir (/var/spool/cron/crontabs): No such file or directory

Workaround:

Mkdir-p/var/spool/cron/crontabs

Since the/var folder is the virtual folder of the kernel and the changes are all gone after the reboot, it can be implemented by self-launching script

Mkdir-p/var/spool/cron//root/root/var/spool/cron/777/var/spool/cron/crontabs/rootcrond

It is not possible to use ' ~ ' because it is executed before login

4) View process consuming memory

The Crond process starts a script implementation on a timed basis, with the following script

Pid= ' PS |grep xxx|sed-n 1p|awk ' {print $} '>>/proc/$PID/status |grep vmsize >> $FILE

Self-modifying according to your kernel printing

All referenced articles and URLs

Crontab Related:

Add timed tasks under Linux

The method of using BusyBox Crond service under embedded Linux

Using BusyBox's Crond service

Linux crontab Timed Task Configuration method (detailed)

View process-related

http://bbs.csdn.net/topics/360001628 (second floor most useful)

View the memory that a program is running under Linux

How much memory is used by processes in Linux under the accuracy amount

Crond Daemon implements timing monitoring of the size of a process that occupies memory