Bash miscellaneous (collection)

Some collected miscellaneous in bash

• Shell expansions order: Brace Expansion, Tilde Expansion, Shell Parameter Expansion, Command Substitution, Arithmetic Expansion, Process Substitution, Word Splitting, Filename Expansion, Quote Removal.
• List operators precedence: && is same as ||, followed by ; and &, which have equal precedence.
• Grouping commands: ( list ) or { list; }.
  () introduces a subshell, while {} does not.
  {} requires last semicolon or newline.
  () does not require begin/end spaces, while {} does
• GNU parallel tool to run command in parallel: -0, -j+0, j 10 are useful options
• Command Line Editing with default emac mode
  Basic:
  C-b, C-f, C-d, C-h: move/delete one character back/forward
  C-a, C-e: move to end/begin of line
  C-l: clear screen
  M-f, M-b, C-w, M-w: move/kill word back/forward
  C-_ ( C-x C-u): undo
  C-k, C-u: kill to end/begin
  C-y, M-y: yank and rotate yank
  C-r, C-s: search back/forward
  C-g: abort
  C-n, C-p, M-<, M->: next/previous/begin/end of history
  C-v <key> (or C-q <key>): print a key
  C-d: EOF
  M-[-]<digit>: add argument
  Others:
  C-t, M-t: transpose char, word
  M-u, M-l, M-c: up/down case word, capitalize word
  M-?, M-*: show/insert possible completions
  M-/, M-~, C-x ~, M-$, C-x $, M-@, C-x @, M-!, C-x !, M-{: completion keys