bash for loop not working as expected

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.?

nneonneo · Accepted Answer · 2013-07-31 02:48:41Z

4

Why use the backticks? Just do

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

answered Jul 31, 2013 at 2:48

nneonneo

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nicky_zs · Accepted Answer · 2013-07-31 02:49:05Z

0

try:

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

answered Jul 31, 2013 at 2:49

nicky_zs

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Andy Jones · Accepted Answer · 2013-07-31 02:57:25Z

0

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.

answered Jul 31, 2013 at 2:57

Andy Jones

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