Using pv to monitor bytes flowing through a pipe, like dd

Sending large files on the command line is often a nerve wrecking experience. Is the file being sent, or am I just going to wait for ever? Fortunately the pv utility can monitor the number of bytes being sent into a pipe.

Instead of sending your file directly, pipe it to the command from pv. For example, to write an image file to a disk, do:

pv -tpreb lubuntu-18.10-desktop-amd64.img | sudo dd of=/dev/disk2 bs=1m

The options used are:
-t “Turn the timer on”
-p “Turn the progress bar on”
-r “Turn the rate counter on”
-e “Turn the ETA timer on”
-b “Turn the total byte counter on”

pv can be used in any pipe. Simply insert pv in the pipe between other commands. For example, to copy a large file using cat (a contrived example, but useful for illustrating):

cat lubuntu-18.10-desktop-amd64.iso | pv | cat >> lubuntu-18.10-desktop-amd64.iso.copy

As a sanity check compare the number of byte in the original and the copy using ls -l :

ls -l lubuntu-18.10-desktop-amd64.iso*
-rw-r--r--- 1 xuser xgrp 1694498816 Nov 1 14:03 lubuntu-18.10-desktop-amd64.iso
-rw-r--r--  1 xuser xgrp 1694498816 Nov 1 17:30 lubuntu-18.10-desktop-amd64.iso.copy

For more options and ways to use pv, refer to the man page.