由Bash执行的脚本与由cron执行的脚本产生不同的结果 [英] Script produces different result when executed by Bash than by cron
问题描述
请考虑使用以下crontab(根):
Please consider following crontab (root):
SHELL=/bin/bash
...
...
0 */3 * * * /var/maintenance/raid.sh
bash脚本/var/maintenance/raid.sh:
#!/bin/bash
echo -n "Checking /dev/md0... "
if ! [ $(mdadm --detail /dev/md0 | grep -c "active sync") -eq 2 ]; then
mdadm --detail /dev/md0 | mail -s "Raid problem /dev/md0" "my@email.com";
echo "ERROR"
else
echo "ALL OK"
fi;
#-------------------------------------------------------
echo -n "Checking /dev/md1... "
...
这就是...
...从shell提示(bash)执行:
输出为mdadm --detail /dev/md0的邮件已发送到我的电子邮件中(正常行为)
Mail with mdadm --detail /dev/md0 output is sent to my email (proper behaviour)
...由cron执行:
空白邮件已发送到我的电子邮件中(主题存在，但没有消息)
Blank mail is sent to my email (subject is there, but there is no message)
为什么会有这种差异以及如何解决?
Why such difference and how to fix it?
推荐答案
如评论中所示，请在crontab脚本上使用完整路径，因为crontab确实具有与普通用户(在这种情况下为root)不同的环境变量.
As indicated in the comments, do use full paths on crontab scripts, because crontab does have different environment variables than the normal user (root in this case).
根据您的情况，/sbin/mdadm代替了mdadm.
In your case, instead of mdadm, /sbin/mdadm makes it.
如何获取命令的完整路径?使用命令command -v:
$ command -v rm
/bin/rm
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