> xchm

Some materials (like old HP-UX training or documentation) is available as CHM files. You can convert them to something else but it the looks like sh*t ... this using xchm(1) helps here. Yes, nowadays it also does not happen that often.

Besides xchm(1) does not look that bad:

- https://www.dedoimedo.com/images/computers/2009/xchm-another...

> xev

I use that to test what keys what codes have. For example with ThinkPad W520 the keys to the left and right of the ARROW keys are 'NEXT' and 'PREV' - I always map them to Page Up and Page Down keys with ~/.xmodmaprc file:

    ! PAGE UP/PAGE DOWN
      keycode 167 = Next NoSymbol Next
      keycode 166 = Prior NoSymbol Prior

... and I use xev(1) in that process first to check what codes are before xmodmap(1) does the job and second time when the new xmodmap(1) config is loaded.

Its not daily but I also do not use nc(1) or traceroute(1) or dig(1) daily but I of course use these tools when needed.

Hope that helps.