bash for循环不按预期工作

Question

I have six openvswitches that I have created using mininet.I want to dump the flow tables using a very simple bash script.For some reason this doesn't seem to be working.

for i in `sudo ovs-vsctl list-br` ; do {`sudo ovs-ofctl dump-flows $i`}  ; done

gives the output

{NXST_FLOW: command not found
{NXST_FLOW: command not found
{NXST_FLOW: command not found
{NXST_FLOW: command not found
{NXST_FLOW: command not found
{NXST_FLOW: command not found

However if I do

for i in `sudo ovs-vsctl list-br` ; do echo $i  ; done

I get the below output.

s1 s2 s3 s4 s5 s6

By the way I am able to do

sudo ovs-ofctl dump-flows s1

and get the right information.

What is wrong with my bash script.?

Answer 1

Why use the backticks? Just do

for i in `sudo ovs-vsctl list-br` ; do sudo ovs-ofctl dump-flows $i ; done

Answer 2

try:

for i in sudo ovs-vsctl list-br ; do sudo ovs-ofctl dump-flows $i; done

Answer 3

You're using command substitution and command grouping all at once.

You told bash to run the command (the backticks) and then treat the output as another command to run.