As idle musing, and a way to show off my mastery of shell pipelines, I was wondering what my most-used shell commands are. It’s an easy few commands to pipe.

history | sed 's/^ *//;s/ \+/ /g' | cut -d' ' -f 2 | sort | uniq -c | sort -n | tail -n 20

The outcome is rather expected. I feel validated (by my shell) in my own self-perception!

As for a less cryptic unpicking,

history             # get the shell's history, as lines of the form '  <nnn>  <command> <arguments>'
  | sed 's/^ *//;   # trim leading spaces
         s/ \+/ /g' # replace multiple spaces with a single one, for all occurrences
  | cut -d' ' -f 2  # cut the line at every single space, and retain the second field (the <command>)
  | sort            # sort the output, as needed by uniq
  | uniq -c         # remove duplicates, but retain a count, as line of the form '<count> <string>'
  | sort -n         # sort the output 
  | tail -n 20      # keep the last 20 lines

Notes:

• Due to the lack of line continuations, this commented command is not functional as is.
• This works with the GNU coreutils on Linux. Other Unices may exhibit slightly different behaviours and/or require the use of g-prefixes commands (e.g., gsed) to use the Coreutils implementation (if installed).