This post appeared originally in our sysadvent series and has been moved here following the discontinuation of the sysadvent microsite
pv is a nice little tool that will take stdin and make a nice little
progress bar and displaying time elapsed, percentage completed (if size is known)
current throughput rate and the total data transferred and with an ETA.
So if you have a tool that can output it’s result on standard output or read from standard input, one can get a progress bar!
It’s nice to know that “data is flowing”.
Other examples
Send file with Netcat and get a nice progress-bar:
pv file | nc -w 1 example.com 3000
Get progress bar on tar output:
tar zcf - /directory | pv > backup.tar.gz
MySQL dump/restore:
mysqldump database | pv > database.sql
pv database.sql | mysql database
Limit the transfer rate and size of data over a pipe
cat /dev/zero | pv -L 3m -Ss 100m > /dev/null
EL9's grubby sorting
So I had this el9 machine that had been sitting quietly waiting for updates for a bit too long. Blinded by courage, I went in and did a
dnf update, rebooted, and lo and behold, it worked without a hitch afterwards. Except just one small one: It did not automatically boot the newest kernel. I tried the standard things. Look at /etc/default/grub, look at the output of various grubby commands. To no avail. It simply would ... [continue reading]