How to add a progress bar to a shell script?

Question

When scripting in bash or any other shell in *NIX, while running a command that will take more than a few seconds, a progress bar is needed.

For example, copying a b

Answer 1

A simpler method that works on my system using the pipeview ( pv ) utility.

srcdir=$1
outfile=$2


tar -Ocf - $srcdir | pv -i 1 -w 50 -berps `du -bs $srcdir | awk '{print $1}'` | 7za a -si $outfile