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amirgol

08-16-2011 04:34 AM

Unable to assign an array in rc.local

I have the following line in my rc.local file:

Code:

USB=( `/usr/bin/file /sys/block/sda | /bin/egrep -o 'usb.*' | /usr/bin/awk -F"/" '{print $1, $2, $3}'` )

It works just fine on any other shell script but in rc.local it stops the execution. I've no idea what happens as this is a headless server, but I know that the internal segment executes just fine: if I place the following line in my rc.local:

Code:

echo `/usr/bin/file /sys/block/sda | /bin/egrep -o 'usb.*' | /usr/bin/awk -F"/" '{print $1, $2, $3}'` >> /root/aaa

I get the expected output (usb1 1-1 1-1.1) in /root/aaa. SO it seems that the array assignment is he culprit here.

Any idea what's happening and how can I solve this? The server is running Debian Wheezy x64.

grail

08-16-2011 05:31 AM

Well I found this with a bit of searching:

Quote:

POSIX and Bourne shells are not guaranteed to have arrays at all.

And then when tested I found the following:

Code:

$ cat test.sh

#!/bin/sh



x=($(/usr/bin/file /sys/block/sda | awk '/^[^0-9]/{c=0}/usb/{c=1}c' RS="/" ORS=" "))



echo "${x[1]}"

$ ./test.sh

./test.sh: 3: Syntax error: "(" unexpected

So I am guessing that this may be happening to you. However, this might help:

Code:

$ cat test.sh

#!/bin/sh



set - $(/usr/bin/file /sys/block/sda | awk '/^[^0-9]/{c=0}/usb/{c=1}c' RS="/" ORS=" ")



echo "$@"

$ ./test.sh

usb9 9-2 9-2:1.0

amirgol

08-16-2011 06:20 AM

Well, my test.sh has no errors ;-). But the same code in rc.local fails. I use the resulting array in a for loop, is there an alternative for it?

grail

08-16-2011 08:15 AM

Quote:

Well, my test.sh has no errors ;-).

When using sh or bash?? It is an important difference as rc normally runs a POSIX shell, generally sh.

Quote:

I use the resulting array in a for loop, is there an alternative for it?

Did you look at my second example??

amirgol

08-16-2011 09:54 AM

Oh, my test file was using bash. Hmm.

Anyway, problem solved: I've learned that a for loop don't need an array, so now everything is working as it should've.

Thanks for the help.

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