mjhjmtu

I would like to use su -c to run as root multiple commands altogether. I don't want to use an extra script for this.

I tried the following:

su root -c "tcpdump -i wlan0 -s 1500 -w CCCCCC & " -c "ls -lh"

but it executes only the ls not the first one.

I tried the following:

su root -c "tcpdump -i wlan0 -s 1500 -w CCCCCC & ; ls -lh;"

but it says that there is an error with the semicolon ;.

Do you know how to do that?

This command runs fine:

su root -c "date; ls -lh"

But in this command:

su root -c "tcpdump -i wlan0 -s 1500 -w CCCCCC & ; ls -lh;"

Since you have & before ; therefore you are getting errors. Try removing & and re-executing the command.

Or you can run your command like this:

su root -c "(tcpdump -i wlan0 -s 1500 -w CCCCCC &); ls -lh"

As anubhava says, your

su root -c "tcpdump -i wlan0 -s 1500 -w CCCCCC & ; ls -lh;"

command is failing because you’re not allowed to have
& followed immediately by ;. 
You can see this just by typing the commands directly into the shell:

• 
  true & true  works


• 
  true & ; true doesn’t work

If you want the tcpdump command to run in the background,
remove the ;, as in

su root -c "tcpdump -i wlan0 -s 1500 -w CCCCCC & ls -lh;"

(and you don't need the ; at the end, either, but it doesn’t hurt).

I think the nohup command will get you what you want too... tcpdump running in the background (no ampersand necessary):

su root -c "nohup tcpdump -i wlan0 -s 1500 -w CCCCCC ; ls -lh"

Just to add to Anubhava's excellent answer:

You could use as well, like this:

su root -c " tcpdump -i wlan0 -s 1500 -w CCCCCC & ; ls -lh"

is a little more efficient than () in that it doesn't create a sub shell. does need a space after and a ; before unless we have an & already.

Use && to separate your commands like so:

$ su -c "ls && ls"