Paginating output from a command line programs seems like it should be easy, but before you go and write it yourself (and discover all the fun of terminal types), I recommend the Click package. Click is a handy little tool for creating command line applications. While it looks like much of the package is devoted to command line args and subcommands, it also has a nice paging utility for relatively small amounts of text.

How To

I was really impressed with how simple Click made paginating the display of a block of text. If you discount some minor refactoring I had to do to make a function work with the click.command decorator, there were really only three changes needed:

1. add import click

2. add @click.command() decorator to my function

3. change the output section from a for loop printing each line to calling click.echo_via_pager('\n'.join(lines))

Pros

Click is well put together, well documented, installed with pip, and worked easily! I was definitely happy with it for my original task, which was paginating a few hundred lines of text.

Cons

I ran another test with a second script, this time using a generator to process tens of thousands of lines of text. The paginator in Click was definitely not designed for this use case and I couldn't make it work.

Conclusion

I was quite happy with how easy Click made the simple task simple. Looking at the documentation, it seems that there are a number of other features which will be handy for some of my bigger projects. I'll definitely be pulling it in for some future projects and refactoring. I hope to have a comparison of click and argparse in a future post.