Highlighting strings in text output with histring

Note, I posted the following on debian-administration.org on Tue 21 Nov 2006. I’ll repost it here with some editing.

Recently there was an article on this site [debian-administration.org] discussing adding colour highlighting to grep. Now we’re going to look at a general purpose highlighting tool called histring.

If you like to work in console more than X, and like text tools more than GUI ones then histring is definitely a tool for you!

histring simply highlights strings using ANSI terminal escape codes. It is extremely small and lighting fast. I almost use it everywhere in my script where I need a quick peek into large output. Moreover, you almost don’t need to learn it, as its syntax is almost identical to grep. The following examples will turn you into a histring-pro in just minutes.

This is a nifty alias that I use more often than anything else, to accept output from diff or rcsdiff to highlight diff files:

histring -fE '^Comparing files .*|^diff .*' | histring -c yellow -fE '^\-.*' | histring -c green -fE '^\+.*'

With that, who needs to wait 0.5 seconds for tkdiff? :-)

Note

  • Someone commented on my OP that there is a special purpose tool especially for highlighting diff outputs, which is “a little easier to use”.
  • oDn commented that histring helped him enjoy the colourful highlighting of the mail log files, then there was a rush of other comments listing other tools that especially for log highlighting.
  • Other people commented that emacs or vim can do good highlighting as well.

I agree that there are all kinds of special purposed highlighting tools out there, and every editors’ highlighting capability are good as well. But, maybe my value is different from theirs, I really don’t get the point of installing a bunch of special purposed highlighting tools for various special tasks, while a single, small and simple tool can take care of them all. This is the beauty of histring, you don’t need to install a bunch of other tools, then learn to use them. One is enough and good for all.

The following two examples can show how general-purpose and versatile histring can be. I believe no other ready-made special-purposed tools or editors can do that.

With the above alias I also wrote another alias to compare rcs file version by version. I guess no other diffing tool has such an ability to show how things evolve.

You can use histring in any situation, not just for diffs and logs. Check this out:

zip -t *.zip 2>&1 | histring -fEi 'warning |bad CRC|error: ' | less

This example will show me the content of my .zip files. More importantly, it will alert me if any of the zip files has any problem.

Once you get used to it, the application situations are endless, and you can’t image the life without it.

histring was originally available from FreeBSD, e.g., the following URL:

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/local-distfiles/roam/misc/

When I wrote my OP, I was able to persuade Michael Prokop from grml.org to create and host a Debian package for it in grml.org repo. But sadly, it was removed several years later. From then on, I had to rely on my saved .deb package file for my histring installation.

Now that I’m starting to maintaining Debian/Ubuntu packages, the first thing I did was to revive it and put it in my Ubuntu PPA.

Hope you enjoy it as I do.

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