Brace expansion

https://www.cyberciti.biz/faq/explain-brace-expansion-in-cp-mv-bash-shell-commands/

echo YOUR_TEXT{1,2,3}.txt

cp /etc/httpd/httpd.{,.BAK}

See also

• Bash, alias, &&, Bash history, Autocompletion, set, unset, export, .bashrc and .bash profile, PS1, echo, brace expansion, Function, shopt, trap, set -e, source, PATH, complete, disown, .hushlogin, .bashrc, builtin, eval, set