How do you monitor the progress of dd?

Question

dd is a wonder allowing you to duplicate a hard drive to another, completely zero a hard drive, etc. But once you launch a dd command, there's nothing to tell you of it's progress. It just sits there at the cursor until the command finally finishes. So how does one monitor dd's progress?

Answer 1

http://linuxcommando.blogspot.com/2008/06/show-progress-during-dd-copy.html

Basically:

kill -USR1 < dd pid >

Answer 2

from HowTo: Monitor the progress of dd

You can monitor the progress of dd without halting it by using the kill command.

To see the progress of dd once it's running, open another terminal and enter:

sudo kill -USR1 \`pgrep ^dd\`

This will display dd progress in the dd terminal window without halting the process. If you would like to get regular updates of the dd progress, then enter:

watch -n5 'sudo kill -USR1 \`pgrep ^dd\`'

watch will probe the dd process every -n seconds (-n5 = 5 seconds) and report without halting it.

Note the proper backticks and single quotes in the commands above.

Answer 3

Install pv and put it between input / output only dd commands.

Note: you cannot use it when you already started dd.

From the package description:

pv - Pipe Viewer - is a terminal-based tool for monitoring the progress of data through a pipeline. It can be inserted into any normal pipeline between two processes to give a visual indication of how quickly data is passing through, how long it has taken, how near to completion it is, and an estimate of how long it will be until completion.

Installation

sudo apt-get install pv

Example

dd if=/dev/urandom | pv | dd of=/dev/null

Output

1,74MB 0:00:09 [ 198kB/s] [      <=>                               ]

You could specify the approximate size with the --size if you want a time estimation.

Other uses

You can also use it to output to stdout:

pv /home/user/bigfile.iso | md5sum

Output

50,2MB 0:00:06 [8,66MB/s] [=======>         ] 49% ETA 0:00:06

Note that in this case, pv recognizes the size automatically.

Answer 4

If you have already started dd, and if you are writing a file such as when creating a copy of a pendrive to disk, you can use the watch command to constantly observe the size of the output file to see changes and estimate completion.

watch ls -l /pathtofile/filename

Answer 5

The best is using http://dcfldd.sourceforge.net/ it is easy to install through apt-get