One of the common command on Linux is to compress or decompress files and folders. While it's easy to do, there is no progress bar for usual command such as Tar, Zip, Importing to Database or Exporting logs. It may be interesting that there are lots of tools to use. However, I found Pipe Viewer very handy and useful.

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.

Some of the benefits of using PV are:

• Total data transferred
• Time elapsed
• Current throughput rate
• Percentage completed
• ETA

To Install PV, follow the guides below depends on your OS:

• CentOS / RHEL: Set up my YUM repository or use RepoForge, then do yum install pv.
• Fedora: Run yum install pv; the "extras" repository may be required.
• Debian / Ubuntu: Run apt-get install pv to get the latest packaged version from unstable / testing.
• Slackware: Use this SlackBuild script.
• Cygwin: Available as a package.
• FreeBSD: Listed on FreshPorts.
• OpenBSD: Listed under ports.
• Solaris: Download binary packages from OpenCSW.
• OpenSolaris: Includes pv version 1.1.4 in the /dev repository (as of build 119). Install with pkg install SUNWpipe-viewer.
• AIX: An RPM from Pawel Piatek is in the downloads section.
• MacPorts: Run port install pv to get the latest version.
• Mac HomeBrew: Run brew update & brew install pv to get the latest version.
• Exherbo: Run cave resolve -x app-misc/pv to get the latest version.
• Gentoo: Run emerge sys-apps/pv to get the latest version.
• IRIX Nekoware: Available in the Nekoware "beta" repository.

As an example, I would like to start with using PV while importing a dump of MySQL database.

You are able to import your .sql file into the database as easy as the command below:

mysql --user=username --password=password database_name < dump.sql

which in short is equivalent to

mysql -u username -p password database_name < dump.sql

Although it seems quite OK, It is not as helpful as it looks when you have a big file. We might have considered better solution as we need to know the status of progress for our record. Therefore, here is the usage of PV while importing our dump.

pv your_dump.sql | mysql -u root database_name

In this case, you are able to see the progress bar just as below:

More examples to Monitor of PV data progress, sent via a Pipe:

1- To copy a file called your_access.log to /tmp/something-access.log and show progress:

pv your_access.log > /tmp/something-access.log

2- To compress a lot of files within a folder and seeing progress bar

tar cf - /folder-with-big-files -P | pv -s $(du -sb /folder-with-big-files | awk '{print $1}') | gzip > big-files.tar.gz

3- To watch how quickly a file is transferred using nc(1):

pv file | nc -w 1 somewhere.com 3000

4- To transfer a file from another process and passing the expected size to pv:

cat file | pv -s 12345 | nc -w 1 majidhajian.com 3000

5- To decompress a huge tar.gz file

pv file.tgz | tar xzf - -C target_directory

All in all, Result of all of them like I added a picture to show, is similar as follow:

12.16MB 0:00:20 [6.06MB/s] [==================>               ] 55%  ETA 0:00:37

I encourage you to read more about this amazing tool and be familiar with that. I have plan to publish another article about screen which is another great tool and combination of both, will make your life as a developer more relaxed.