SSH and script weirdness

[philsto]

We have created a script to capture an image from a webcam and deposit it into a folder so it is available to the web.

The script was created by a colleague who SSHd into the server and placed the script on the root level in a folder called scripts.

the script works flawlessly when he kicks it off as sudo from the SSH connection. It deposits a 50Kb file into the folder and all looks great.

When I initiate the script locally via sudo I also get a file in the folder. Problem is it’s 0Kb, and there’s no there there…

Looked at all the permissions, and they look all right…

Any ideas?

Thanks

Phil

[khiltd]

What’s in the script and why does it need root privileges to copy a file?

[philsto]

Here is the script….

My misunderstanding, the script does not require root under ssh. it runs fine as any user. However, it also creates 0 Kb files when initiated from terminal on the server itself…
#!/bin/bash

HOST_IP=0.0.0.0
IMAGE_URL=http://0.0.0.0/jpg/1/image.jpg
IMAGE_DIR=/Volumes/Data/Webserver/File
W_DIR=/scripts
SLEEP_TIME=30
HOST_REACHABLE=1

grab()
{

D=`date +%F%p`

echo “Checking the server.”

ping -c 1 $HOST_IP &> /dev/null

if [ $? = 0 ]; then
HOST_REACHABLE=1

echo “Getting image file.”

/opt/local/bin/wget -N $IMAGE_URL > $W_DIR/image.jpg

if [ $? = 0 ]; then
echo “Archiving…”
mv $W_DIR/current.jpg $W_DIR/bak/image.$D.jpg
if [ ! -s $W_DIR/image.$D.jpg.gz ];
then gzip -c $W_DIR/bak/image.$D.jpg > $W_DIR/bak/image.$D.jpg.gz
fi
rm $W_DIR/bak/image.$D.jpg
echo “Updating..”
mv $W_DIR/image.jpg $W_DIR/current.jpg
ditto $W_DIR/current.jpg $IMAGE_DIR/current.jpg
echo “Done.”
else
echo “Error: Image Not Found”
HOST_REACHABLE=0
fi

else
echo “Error: Host Unreachable”
HOST_REACHABLE=0
fi
}

while [ $HOST_REACHABLE = 1 ]; do
grab
echo “Sleeping…”
sleep $SLEEP_TIME
done

exit 0

[khiltd]

What if you lose the -N option on wget?

[philsto]

Hey there,

It’s our understanding that –N option on wget just tells it to continue saving the file in the same spot, otherwise, if you download the same file to a directory twice, regardless of whether you have deleted the original, it will name the new one “filename.1”. This would make it difficult to write a script for, since the file name would constantly be changing.

Is that a misunderstanding of the function, or does it have some other effect which may have gotten in the way?

Phil

[khiltd]

I think you’ve misread the documentation:

[code]-N, –timestamping don’t re-retrieve files unless newer than local.[/code]

[philsto]

Yeah, it looks like it…. We’ll try that, thanks.

Phil

[Author]

Posts