Re: Cron problem!

[高超 <achaoge@163.com>]

Hongbo Ma wrote:

>I wrote a script called full_backup.sh to do bakcup. It is supposed to
>run at a given time everyday. I log in as root, and type "crontab -e"
>add a entry like following to the crontab file:
>*******************************
>15  18   *    *    *    /usr/local/bin/full_backup.sh 
>********************************
>
>
>The content of the full_backup.sh (I put it under /usr/local/bin) is:
>
>******************************************
>#!/bin/sh
>mt -f /dev/nst0 rewind
>
>rm /var/log/tar/snapshot
>
>tar -cvpf /dev/nst0 --label="Full Backup Set Created
>on `date '+%d-%B-%y'`." --listed-incremental=/var/log
>/tar/snapshot /home/hma/project
>*******************************************
>
>I can run this script with no problem manually and get my archive file
>on tape. However, if I use cron, although it IS  triggered by cron, the
>'tar' command in the script didn't run successfully. That is to say, I
>know the script was executed by checking the consequence of
>"rm /var/log/tar/snapshot", but I didn't get the archive file on tape.
>
>Strangely, if I changed the backup target directory from  the
>"/home/hma/project" to "home/hma/proposal", then every thing is fine. I
>get the archive file on tape. "proposal" directory is about 3MB, while
>"project" directory is about 700MB. But the size should not be a
>problem, since I can manually run the script to backup "project"
>correclty.
>
>Obiousely, something is wrong with my cron, but I just don't know how to
>correct it. Currently, I don't have sendmail program installed on my
>system, so I can't get the email cron is supposed to send to me. 
>
>Any help is highly appreciated!!
>
>Hongbo Ma
>
>
>  
>
cron 文件里面命令用绝对路径比较好，毕竟在命令行下执行时有路径的环境变
量，到了cron里面就没有了。

或者你在cron文件里面定义也可以。