Question

Strange thing. I have a shellscript that needs to be run with sudo since it uses dumpcap.

#!/bin/bash
# Simulates the transmissions with Sirannon

mkdir -p 3dvideos_streamed
mkdir -p 3dvideos_packetcapture

for file in Alt_moabit Book_arrival Door_flowers Leaving_laptop
do
  for qp in 10 15 25 32 45 60
  do
    echo "Now simulating transmission of $file with QP $qp ... "

    echo "Starting dumpcap ... "
    touch 3dvideos_packetcapture/$file-$qp.cap
    dumpcap -i lo -f "udp port 5000" -a duration:15 -w 3dvideos_packetcapture/$file-$qp.cap &

    cp 3dvideos_encoded/$file/qp$qp/test.264 3dvideos_streamed/$file-$qp-in.264 &

    echo "Starting sirannon ... "
    sirannon sirannon-0.6.8/dat/xml/mvc.xml 3dvideos_encoded/$file/qp$qp/test.264 3dvideos_streamed/$file-$qp 3dvideos_streamed/$file-$qp-out.264
    echo "Sirannon is done streaming."

    sleep 15    

  done
done

echo "Fixing permissions ... "
chmod -R 655 3dvideos_streamed
chmod -R 655 3dvideos_packetcapture

Now I’m left with this:

werner@savant:~/CACMTV$ ls -la 3dvideos_packetcapture/
ls: cannot access 3dvideos_packetcapture/Alt_moabit-60.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Book_arrival-60.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/..: Permission denied
ls: cannot access 3dvideos_packetcapture/Leaving_laptop-10.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Leaving_laptop-32.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Leaving_laptop-60.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Alt_moabit-25.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/.: Permission denied
ls: cannot access 3dvideos_packetcapture/Door_flowers-10.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Door_flowers-15.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Book_arrival-15.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Leaving_laptop-15.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Door_flowers-25.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Alt_moabit-10.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Door_flowers-32.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Leaving_laptop-25.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Book_arrival-45.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Alt_moabit-45.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Door_flowers-45.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Book_arrival-10.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Alt_moabit-15.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Door_flowers-60.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Leaving_laptop-45.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Alt_moabit-32.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Book_arrival-25.cap: Permission denied
ls: cannot access 3dvideos_packetcapture/Book_arrival-32.cap: Permission denied
total 0
d????????? ? ? ? ?                ? .
d????????? ? ? ? ?                ? ..
-????????? ? ? ? ?                ? Alt_moabit-10.cap
-????????? ? ? ? ?                ? Alt_moabit-15.cap
-????????? ? ? ? ?                ? Alt_moabit-25.cap
-????????? ? ? ? ?                ? Alt_moabit-32.cap
-????????? ? ? ? ?                ? Alt_moabit-45.cap
-????????? ? ? ? ?                ? Alt_moabit-60.cap
-????????? ? ? ? ?                ? Book_arrival-10.cap
-????????? ? ? ? ?                ? Book_arrival-15.cap
-????????? ? ? ? ?                ? Book_arrival-25.cap
-????????? ? ? ? ?                ? Book_arrival-32.cap
-????????? ? ? ? ?                ? Book_arrival-45.cap
-????????? ? ? ? ?                ? Book_arrival-60.cap
-????????? ? ? ? ?                ? Door_flowers-10.cap
-????????? ? ? ? ?                ? Door_flowers-15.cap
-????????? ? ? ? ?                ? Door_flowers-25.cap
-????????? ? ? ? ?                ? Door_flowers-32.cap
-????????? ? ? ? ?                ? Door_flowers-45.cap
-????????? ? ? ? ?                ? Door_flowers-60.cap
-????????? ? ? ? ?                ? Leaving_laptop-10.cap
-????????? ? ? ? ?                ? Leaving_laptop-15.cap
-????????? ? ? ? ?                ? Leaving_laptop-25.cap
-????????? ? ? ? ?                ? Leaving_laptop-32.cap
-????????? ? ? ? ?                ? Leaving_laptop-45.cap
-????????? ? ? ? ?                ? Leaving_laptop-60.cap

I can see the files in Nautilus, but I can’t open them:

How do I fix this – how would I need to change my shellscript in order for dumpcap to have the necessary permission but at the same time leave my permissions intact?

Answer 1

It turns out the easiest solution is to just run the command as:

sudo ./script.sh -u werner

Then all lines with chmod/chown are not needed.