= bash
== I/O redirection

0  stdin
1  stdout
2  stderr

cmd &>FILE       # send stdout & stderr to FILE
cmd 2>&1         # redirect stderr to stdout
>&2 echo "ERROR" # write to stderr

maybe useful settings?!
  shopt -s autocd cdspell dirspell checkjobs globstar histappend




== advanced tutorials/notes

https://tldp.org/LDP/abs/html/index.html
https://linuxcommand.org/tlcl.php
https://mywiki.wooledge.org/FullBashGuide
https://mywiki.wooledge.org/BashFAQ
https://github.com/anordal/shellharden/blob/master/how_to_do_things_safely_in_bash.md

== snippets
=== remove file extension

FILENAME=hello.txt
echo "${FILENAME%.*}"

=== default string

PROVIDED_USERNAME="lukas"
export USERNAME="${PROVIDED_USERNAME:=defaultusername}"