sudo bashfile makes syntax error

Question

i have got a bash file which i want to toggle via the sudo crontab list. Problem is, that it does not work, because when i run the script with sudo, there is a syntax error message on this line:

size=(`du -h $backupDir --summarize`)

If i run the same script without, i have to type the sudo pw, but it works without any problems. I allready tried a few variations with brackets, with or without backticks, with or without spaces, etc but nothing helped. The error message is:

Syntax error: "(" unexpected (expecting ";;")

Any help?

Answer 1

The problem here is that you use bash-syntax, and the script (when it is executed from cron) is interpreted by /bin/sh (that known nothing about arrays and the () construction.).

You must either specify bash as an interpreter of the script using she-bang notation:

#!/bin/bash

or run the script explicitly with bash from cron:

bash /path/to/script

or rewrite script so, that it could run without arrays.

Answer 2

Fro readability use the $() form

size=$(du -h $backupDir --summarize)

If you want to stick to back quotes, then

size=`du -h $backupDir --summarize`