Question

Here’s what I am trying to do:

time sh -c "dd if=/dev/zero of=ddfile bs=512 count=125 && sync"

When run that on shell the o/p is

125+0 records in
125+0 records out
64000 bytes (62.5KB) copied, 0.028935 seconds, 2.1MB/s
real 0m 0.08s
user 0m 0.00s
sys 0m 0.01s

I want to capture the output to a variable or to a file. How do I do that ?

Thanks!

Answer 1

You can do:

(time sh -c "dd if=/dev/zero of=ddfile bs=512 count=125 && sync") 2> file

Since you need to redirect the output of both time and dd you need to enclose the entire thing in (..).

Both time and dd send their output to stderr, so using > will not work, you need 2> which redirects stderr.

To get the output in a variable you can do:

var=$((time sh -c "dd if=/dev/zero of=ddfile bs=512 count=125 && sync") 2>&1)