Bash脚本有效，但从crontab执行时无效 [英] Bash Script works but not in when executed from crontab

问题描述

我是Linux新手，下面的脚本只是我的问题的一个示例：

I am new to linux and the script below is just an example of my issue:

我有一个脚本，该脚本在执行时可以按预期工作，但是在我执行时将其设置为通过crontab运行，由于无法将文件内容读入变量，因此无法按预期运行。

I have a script which works as expected when I execute it however when I set it to run via crontab it doesn't work as expected because it doesn't read the file content into the variable.

我有一个文件 test.txt，其中包含 abc。我的脚本将文本放入变量'var'，然后将其回显到日志文件：

I have a file 'test.txt' which has 'abc' in it. My script puts the text into a variable 'var' and then I echo it out to a log file:

var=$(</home/pi/MyScripts/test.txt)
echo "$var" >/home/pi/MyScripts/log.log

当我执行它并使其回显到日志文件中时，它可以很好地工作，但是当我通过crontab对其进行设置时，它不是：

This works perfectly fine when I execute it and it echo's into the log file but not when I set it via crontab:

* * * * * /home/pi/MyScripts/test.sh

cron作业运行，并且向我发送了以下错误消息：

The cron job runs, and it sent me the following error message:

/bin/sh: 1: /home/pi/MyScripts/test.sh: Permission denied.

但是我已授予777权限：

But I have given it 777 permissions:

-rwxrwxrwx 1 pi pi   25 Jun 10 15:31 test.txt
-rwxrwxrwx 1 pi pi   77 Jun 10 15:34 test.sh

有什么想法吗？

推荐答案

当您使用其他Shell运行脚本时，会发生这种情况。对于 / bin / sh 为 dash 的系统尤其重要：

This happens when you run the script with a different shell. It's especially relevant for systems where /bin/sh is dash:

$ cat myscript 
echo "$(< file)"

$ bash myscript
hello world

$ sh myscript

$ 

要修复此问题，请添加＃！/ bin / bash 作为脚本的第一行。

To fix it, add #!/bin/bash as the first line in your script.

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