Hacker News Reader

Comment by scarygliders | Hacker News Reader

Another one:

Use dcfldd instead of dd if you want to see how far your dd operation is progressing...

dcfldd if=[infile] of=[outfile] sizeprobe=if

So. Much. Better.

dcfldd also has many other useful options - read the man pages - and note that you'll have to install it from your linux distro's package repo beforehand.

View on HN

You can also send SIGUSR1 to dd for progress info. From the manpage:

  Sending a USR1 signal to a running 'dd' process makes it print I/O statistics to standard error and then resume copying.

    $ dd if=/dev/zero of=/dev/null& pid=$!
    $ kill -USR1 $pid; sleep 1; kill $pid

    18335302+0 records in 18335302+0 records out 9387674624 bytes (9.4 GB) copied, 34.6279 seconds, 271 MB/s

Indeed you can :)

But I prefer not to have to manually keep sending that ;)

while ; do kill -s USR1 $(pgrep '^dd$'); sleep 5; done

On OSX it's SIGINFO (29) in case anybody wondered

Which you can also get by hitting Ctrl-T. This works for FreeBSD too. (Not sure about the other BSDs.)

neato

It works on all of them, including OSX.

Caution: while this works great on Linux, on OSX, a USR1 will kill dd, and a SIGINFO will get you the block counts.

Indeed, looks like GNU coreutils dd responds to SIGUSR1 on linux and SIGINFO on linux. That's good to know. What's the reason for this discrepancy?

OSX inherited SIGINFO from the BSDs, OpenBSD, FreeBSD, Dragonfly, and NetBSD all have it.

Linux doesn't. I don't know why; but Google in the past has told me that patches to add it were rejected about 10 years ago.

Just pipe dd to pv

Reply on news.ycombinator.com