sed regex cheatsheet
====================

.          any character, including newline
\n         newline
\char      escaping special characters
*          quantity 0-infinity
\+         quantity 1-infinity
\?         quantity 0-1
\{i\}      quantity i
\{i,j\}    quantity i-j
\{i,\}     quantity i-infinity
\(regexp\) grouping
^          beginning of pattern
$          end of pattern
[list]     character list
[f-t]      ranged character list
[^list]    complemented character list
r1\|r2     alternation (LTR association)
\digit     back reference

Based on https://www.gnu.org/software/sed/manual/html_node/Regular-Expressions.html